Diamond Certified Companies are Rated Highest in Quality and Helpful Expertise.

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Diamond certified companies are top rated and guaranteed

Why Trust Diamond Certified Auto Diagnostic Shops Rated Highest in Quality?

The shop works on both foreign and domestic makes, as well as hybrids. Photo: Orinda Motors, Inc. (2015)

SAN RAMON—You are the customer. If your goal is to choose an auto diagnostic shop that will deliver high customer satisfaction and quality, you’ll feel confident in choosing a Diamond Certified auto diagnostics center. Each has been rated Highest in Quality in the most accurate ratings process anywhere. And you’re always backed by the Diamond Certified Performance Guarantee. Here’s why the Diamond Certified ratings and certification process will help you find a top-rated automotive diagnostic shop and is unparalleled in its accuracy, rigor and usefulness:

You are the customer. If your goal is to choose an auto diagnostic shop that will deliver high customer satisfaction and quality, you’ll feel confident in choosing a Diamond Certified auto diagnostics center. Each has been rated Highest in Quality in the most accurate ratings process anywhere. And you’re always backed by the Diamond Certified Performance Guarantee. Here’s why the Diamond Certified ratings and certification process will help you find a top-rated automotive diagnostic shop and is unparalleled in its accuracy, rigor and usefulness: in its accuracy, rigor and usefulness:

1) Accuracy: All research is performed by live telephone interviews that verify only real customers are surveyed, so you’ll never be fooled by fake reviews.

2) Statistical Reliability: A large random sample of past customers is surveyed on an ongoing basis so the research results you see truly reflect a Diamond Certified company’s top-rated status.

3) Full Disclosure: By clicking the name of a company above you’ll see the exact rating results in charts and read verbatim survey responses as well as researched articles on each qualified company.

4) Guaranteed: Your purchase is backed up with mediation and the Diamond Certified Performance Guarantee, so you can choose with confidence.

Click on the name of a Diamond Certified company above to read ratings results, researched articles and verbatim customer survey responses to help you make an informed decision.

More than 200,000 customers of local companies have been interviewed in live telephone calls, and only companies that score Highest in Quality in customer satisfaction–a 90+ on a 100 scale–as well as pass all of the credential-based ratings earn Diamond Certified. By requiring such a high score to qualify, the Diamond Certified program eliminates mediocre and poorly performing companies. Read detailed information about the ratings and certification process.

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John Vanek is a 43-year veteran of the auto repair industry and manager of Orinda Motors, Inc., a Diamond Certified company since 2002. He can be reached at (925) 709-4934 or by email.

John Vanek

diamond certified contributor profile and expert article

John Vanek: Auto Motivated

By James Florence, Diamond Certified Resource Reporter

ORINDA — While people become involved in the auto repair industry for a variety of reasons, John Vanek’s motivation came primarily from the heart. “I’m one of those guys in the business who really loves cars,” he affirms. “I love working on them, driving them and just about everything else. Even when I’m not at the shop, you’ll often find me working on one of my personal restoration projects at home, which include a 1953 Chevy pickup and a 1936 Ford sedan.”

Thanks to a close family connection in the industry, John was able to jumpstart his automotive career at an early age. “When I was a kid, my older brother opened his own repair shop,” he remembers. “I started out sweeping the shop when I was 15, and I eventually worked my way up to servicing the vehicles.” After 24 years working at his brother’s business, John moved on to the shop he currently manages, Orinda Motors, Inc.

A native of the East Bay, John was born in Berkeley and now lives in El Sobrante, where he appreciates the outdoor opportunities afforded by the local landscape. “My wife, Barbara, and I enjoy going on walks and hikes so we can take in scenic views while getting fresh air and exercise,” he says. “There are a lot of places to do that here, including Tilden Regional Park, which is pretty close to our house.”

Outside of work, John engages in a variety of hobbies and pastimes, from restoring old cars to playing music. “Besides cars, music is my biggest passion. My main instrument is the drums, but I also play guitar and bass.” John also keeps up with his and Barbara’s grown children, Kyle and Sarah, both of whom live locally. Furthermore, as members of the local Elks Lodge, he and Barbara invest a significant amount of time into giving back to their community. “The Elks Lodge does a lot for local charities, including annual fundraising events like dances and pasta feeds, so it’s very rewarding to be a part of that.”

In his life and career, John espouses the importance of treating others fairly and honestly. “I treat people the same way I like to be treated, which is a big part of living with honesty and integrity. Auto repair is an expensive investment, so I always try to use my knowledge and experience to help my customers make good decisions and hopefully save some money in the process.”

When asked the first thing he’d do if he could retire tomorrow, John says he’d take some time to go exploring. “I’d probably go on a big backpacking trip—nothing outrageous, maybe just some trails around Yosemite. There’s also a trail up north called the Lost Coast Trail that I’d like to do. Other than that, I would spend more time working on my cars and playing music.”

Ask Me Anything!

Q: What was your first car?
A: A Datsun 510.

Q: If you could drive any car, what would you choose?
A: A 2014 Ford Mustang Shelby GT500.

Q: If you had a theme song, what would it be?
A: “Don’t Stop Believin’” by Journey.

Q: What was your favorite toy as a child?
A: My Tonka trucks.

Q: What’s the best gift you’ve ever received?
A: The Ibanez acoustic-electric bass guitar my wife gave me for our 20th anniversary.

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The Importance of Properly Functioning Shocks


ORINDA — Shocks are an important yet often overlooked aspect of a vehicle’s operation. The basic function of shocks is to absorb the turbulence (bumps and jolts) of driving on the road—not only to provide a more comfortable ride, but… Read more

Expert Video Tip

Video: Suspension System Awareness and Safety

Complete Video Transcription:

ORINDA — Host, Sarah Rutan: To keep your car running smoothly, it’s important to know how each part of its system works. Today, we’re in Orinda with… Read more




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Chevy Silverado
Dodge Ram Pickup
Ford F-150
Chevrolet Equinox
Chevrolet Impala
Hyundai Elantra
Hyundai Sonata
Kia Sorento
Ford Fiesta
Ford Focus
Ford Mustang
GMC Sierra
Honda Accord
Honda Civic
Honda CR-V
Honda Odyssey
Nissan Murano
Subaru Outback
Toyota Camry
Mazda MAZDA 3
Mercedes-Benz E-Class
Nissan Altima
Dodge Caravan
Lexus LS
Jeep Wrangler
Toyota Corolla
Toyota Sienna
Toyota RAV4
Volkswagen Jetta
Toyota Tacoma

diagnose car trouble
auto overheating diagnostic
auto alternator diagnostics
foreign vehicle diagnosis
domestic vehicle diagnostic
exhaust system diagnostics
ignition coil trouble shooting
fuel pressure tests
on board diagnostic checkup
vehicle air flow diagnostics
auto sensor circuit diagnosis
engine oil sensor diagnostic tests
complete automotive diagnostics
auto air conditioning diagnostics
auto electrical diagnostics
check engine light diagnostics
auto troubleshooting
auto engine diagnostic
auto transmission troubleshooting
auto brake troubleshooting
auto diagnostic scans
auto mechanic troubleshooting
auto starter diagnostics
automotive cooling system diagnostic
automotive fuel pump troubleshooting
troubleshooting for cylinder misfire
crankshaft diagnostics
camshaft diagnostics
car emissions troubleshooting
auto cooling fan diagnostics

Bay Point
Bethel Island
Discovery Bay
El Cerrito
El Sobrante
Hilltop Mall
Los Medanos
North Richmond
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Point Richmond
Port Chicago
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Rheem Valley
San Pablo
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Walnut Creek
Walnut Heights
West Pittsburg


American Automobile Association (AAA) (http://www.aaa.com/)
Automotive Service Association (ASA) (http://www.asashop.org/)
Alliance Of Automotive Service Providers (AASP) (http://www.autoserviceproviders.com/)
National Institute for Automotive Service Excellence (ASE) (http://www.asecert.org/)
California Bureau of Automotive Repair (BAR) (http://www.autorepair.ca.gov/)
California State Automobile Association (CSAA) (http://www.csaa.com/)
International Automotive Technicians Network (IATN) (http://www.iatn.net/)

Know What You Want
Know What You Really Want from Contra Costa County Auto Diagnostics Shops

Before you start looking for an automotive diagnostics shop in Contra Costa County that serves Concord, Walnut Creek, Richmond, Pittsburg, Antioch, San Ramon, Danville, Brentwood, Martinez, Pleasant Hill or your neighborhood, think about the specific auto diagnostics questions you have.

Write a few ideas down. Maybe you are thinking about finding a diagnostic center that has fair rates for automotive troubleshooting services, or you are most interested in getting a good quality diagnosis, or perhaps you want a mobile troubleshooting service. You may want someone to take time going through diagnostic issues with you, or fully explain the diagnostic codes that result.

Being precise about your OBD needs will help a lot as you hear the responses of body repair shops.
Here are several questions to get you started:

  1. Do I want to hire a Diamond Certified company that is rated Highest in Quality and has the Diamond Certified Guarantee?
  2. Do I want a complete automotive diagnostics shop that has been in business in Alameda County for a long time?
  3. What process will be involved to estimate the cost of repairing the diagnostic problem, and what are the prices for some typical causes of OBDII failure?
  4. Is it important to me to find a local auto troubleshooting shop with technicians that have professional certifications?
  5. Do I want the automotive troubleshooting shop I choose to have evidence of good standing with previous customers?
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What To Ask In Person
What to Ask Contra Costa County Auto Diagnostics Representatives in Person

You may visit some on-board diagnostic (OBD) places in Concord, Pittsburg, Walnut Creek, Antioch and Richmond and other areas of Contra Costa County. Questions like the following may help you choose between diagnostic scan shops:

  1. Is it likely that my diagnostic problem can be determined and repaired quickly?
  2. What exact process will typically take place to track down the common causes of OBDII diagnostic trouble codes, and what are the costs for some typical repairs?
  3. How likely is it that the initial estimates for my diagnostic scan and repair work will be the right amount?
  4. How should we communicate during my OBD diagnostic scan and repair process?
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  • What To Ask References
    Learn From Former Auto Diagnostic Shops’ Customers

    How do you really know if customers of a particular auto diagnostics shop in Contra Costa County have really gotten good OBD diagnostic work quality for their time and money? Has a particular diagnostic scan shop satisfied them?

    That’s a huge issue, perhaps the most important one, and not so easy to answer unless you have good independent information.  Diamond Certified auto diagnostics shops give OBD shop consumers a big advantage in Contra Costa County and the greater Bay Area. You can be sure of quality with Diamond Certified companies.

    Consider the value of being able to read word-for-word answers to a number of auto diagnostics customer surveys for Contra Costa County. You won’t be left with limited or misleading OBD customer satisfaction info, because you will have access to the researched opinions of numerous diagnostic scan customers. And you will have the Diamond Certified Performance Guarantee.

    If you can’t find a Diamond Certified auto diagnostics shop, check the shop’s references yourself, and don’t be careless. OBD diagnostic shops may give you some recent customers you can talk to. But that’s not the same as the randomly selected customers of the Diamond Certified ratings process. That’s because a shop can provide customers with good experiences and keep you away from those with bad ones.

    If you do call OBD shop customers,  ask for a list of recent auto diagnostics shop users (to avoid the diagnostic scan shop giving you only satisfied people). Ask a few general questions about their experience with technicians and specific questions about the diagnostic and repair process.  Questions could include:

    1. What OBDII diagnostic trouble did the shop find, and how much repair was necessary for the diagnostic problem?
    2. Did you feel good about the overall auto diagnostics process?
    3. Were you okay with the amount of time the diagnostic work and OBD repair work took?
    4. Did the auto diagnostics people treat you well and explain things fully?
    5. Was the auto diagnostics cost reasonable, and close to the estimate?
    6. What parts of the diagnostic work were done particularly well by the OBD shop?
    7. Will you go back with any more auto diagnostics work?
    8. Do you recommend this OBD shop?
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  • Review Your Options
    Hire a Trustworthy Auto Troubleshooting Service in Contra Costa County

    The Diamond Certified symbol has been awarded to companies that scored Highest in Quality in an accurate ratings process.

    You may feel ready to make an auto diagnostics shop choice at this point.

    Before finalizing it though, think about these auto diagnostics issues:

    1. Can an auto diagnostics shop in Contra Costa County do all of the really important things, including giving fast and friendly service, low cost, and good quality?
    2. Will the auto diagnostics shop reps take care of you with directness and  courtesy?
    3. Is the auto diagnostics shop respected by customers in Contra Costa County for auto diagnostics and OBDII failure code work?

    The last question to ask before you finally choose your auto diagnostics shop in Contra Costa County is this: Do I have good reason to think I have found an auto diagnostics shop that will really meet the automotive troubleshooting needs I have identified?

    In particular, think about the importance of the reliable customer satisfaction info you always get with a prequalified and guaranteed Diamond Certified auto diagnostics company.

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  • How To Work With
    Consider Ways to Cooperate with the Best Auto Diagnostics Shops in Contra Costa County

    In the state of California, auto diagnostics facilities will always be licensed by the Bureau of Automotive Repair, but you want to know that the one you have chosen will best solve your OBD diagnostic trouble code problems.

    All Diamond Certified automotive diagnostics shops are carefully checked in advance for high quality.  If you don’t choose a Diamond Certified shop in Contra Costa County, you should search carefully yourself for a shop that can really meet your auto diagnostic needs.

    OBD shops in the larger Contra Costa County cities of Pittsburg, Concord, Antioch, Walnut Creek and Richmond may have more experience or better certifications than do other auto diagnostics garages, and the technicians there may have diagnostic certifications.

    Now that You Have the Auto Diagnostics Shop, Get Accurate Estimates
    Be sure you understand the diagnostic and repair work you need, or may need once the diagnostic trouble code has been fully worked through. You should be comfortable with the OBD facts and the possible repair choices. Ask questions as needed, and make notes on the responses.

    Remember to find out in advance exactly what the basic diagnostic process will cost, and to arrange to be given an estimate for any repair work based on the OBDII diagnostic trouble codes before it is started.

    Sign a Contract for Auto Diagnostics Work in Contra Costa County, Including Diagnostic Scans in the Larger Cities of Pittsburg, Concord, Antioch, Walnut Creek and Richmond
    When you’re good with the cost info from the Contra Costa County auto diagnostics shop, sign the estimate and OBD service contract.

    Be certain that the auto diagnostics place has the best phone number or numbers for getting you while the diagnostic and repair process is underway.

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  • Be a Good Customer
    Ways You Can Be a Good Auto Diagnostics Shop Customer

    Good diagnostic and repair service is the Contra Costa County auto diagnostics shop’s area of responsibility.  But you have your part in the process also. Here are some thoughts:

    • Be simple and direct with the diagnostics shop people
    • Be friendly with them and polite in talking about OBD matters.
    • Be clear on when to call or be called about auto diagnostics work updates.

    It works for you and for the OBD shop when you take the time to be a good auto diagnostics service customer. The Contra Costa County auto diagnostics shop will work well with good customers.

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Check The Work
Check the Completed Auto Diagnostics Work Against Your Written Invoice

When the auto diagnostics work is done, your shop must provide:

  1. The auto diagnostics shop ID number.
  2. The auto diagnostics and repair work description.
  3. The total price charged for auto diagnostics labor and parts.
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Written Warranties
Get Warranties from Contra Costa County Auto Diagnostics Mechanics

Confirm warranties at the auto diagnostics shop before you leave.

For your protection, the warranty document should include the following:

  1. The auto diagnostics shop’s license number, contact information and physical address.
  2. Description on what’s covered by the automotive diagnostics service, including reworking or cash back.
  3. Instructions for taking action on the auto diagnostics warranty.
  4. The length of time for which the vehicle troubleshooting services warranty is active.
  5. All terms, limitations and exclusions should be listed clearly on the proof of warranty document.
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Top 10 Requests
Automotive Diagnostic Services in Contra Costa County and the Bay Area

The following items are some common auto diagnostic issues handled by local automotive troubleshooting services in Contra Costa County.

Complete Auto Diagnostics
Local auto troubleshooting shops can perform complete auto diagnostic tests and print out a complete report with a set of codes that outline all found problems. Automotive diagnostic tests can diagnose ignition timing problems, excessive buildup in the engine, fuel injector problems, ignition coil diagnostics, exhaust system diagnostics, fuel pressure testing, vehicle air flow diagnostics, auto sensor circuit diagnostics, engine RPM levels, auto coolant temperature, crankshaft problems, camshaft position and the throttle opening malfunctions among other problems.

Auto Electrical Diagnostics
Dimming lights, trouble starting the car, sputtering and other issues can be signs of auto electrical problems. Auto electrical diagnostics test the electrical systems within the vehicle and give unique codes for each type of auto electrical malfunctions possible.

Auto Troubleshooting
General troubleshooting diagnostics are run to test engine oil sensors, auto alternator diagnostics, overheating problems and other car trouble diagnoses in domestic and foreign cars.

Auto Engine Diagnostics
Cars with engine trouble can have auto engine diagnostics run to narrow down the trouble to the underlying problem. Doing this preventatively or when small auto engine problems occur can prevent auto engine failure and more expensive problems down the road.

Auto Starter Diagnostics
Glitchy starters, choking, sputtering and failure to start are some signs that your vehicle may need auto starter diagnostic tests. These can pinpoint the origin of the auto starter problems, and can give your mechanic a clear path to follow to repair your auto starter problems.

Exhaust System Diagnostics
Lit check engine lights often are a sign of exhaust system problems. Troubleshooting can narrow down the codes to outline the exact exhaust system failure or trouble. This can prevent harmful gasses or pollution to be unduly released into the air and can help your car run more cleanly and efficiently.

On Board Diagnostics Checkup
On board diagnostics, including OBD I and OBD II, are the on-board diagnostic systems that point out potential problems in many newer-model vehicles. OBD diagnostic checkups are easy to run with the proper troubleshooting computers and codes.

Auto Air Conditioning Diagnostics
These diagnostic tests can give you the details on your auto air conditioning performance. Auto AC diagnostics may test the cooling system, coolant levels and AC refrigerant levels.

Check Engine Light Diagnostics
Check engine light diagnostics are some of the most common automotive troubleshooting codes run. Check engine lights can be triggered by several problems, but commonly pertain to auto emissions trouble. Auto exhaust system diagnostics are often run to rule out any serious problems with the exhaust systems.

Automotive Cooling System Diagnostics
Auto engine cooling and auto AC systems may need auto diagnostics from time to time to keep tabs on their function and any underlying problems. Automotive cooling system diagnostics can help your mechanic diagnose problems that are otherwise hard to troubleshoot.

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Glossary Of Terms
Glossary of Auto Troubleshooting Terms

Below are some auto troubleshooting terms which may be of help in understanding diagnostic services:

auto diagnostics
Discovering the exact cause of what’s wrong with your car. Auto diagnostics now-days especially means on-board diagnostics (OBD) readable from each car’s individual computer, for smog control purposes.

Also known as: diagnostic, auto diagnostic, OBD, OBDII, OBD2

auto diagnostic equipment
The diagnostic tools for reading the OBDII diagnostic trouble codes from your car’s computer. This can be done with a diagnostic code reader or a diagnostic scan tool.

Also known as: diagnostic, diagnostic tools, auto diagnostics, OBDII diagnostic scan tool

auto diagnostic scan
The process of reading your car’s computer, or PCM, for diagnostic trouble codes indicated by the Check Engine Light coming on. The diagnostic scan is done with an OBD diagnostic tool known as a scan tool.

Also known as: diagnostic tool, OBD diagnostic scan tool

auto diagnostic standardization
One of the main purposes of OBDII. In 1996, OBDII brought standardized connectors, standardized protocols, and other standardized elements to improve diagnostics for emission problems.

catalytic converter failure
One of the main causes of OBD diagnostic failure codes, Check Engine Light displays, and emission test failures. The catalytic converter turns various exhaust air pollutants, including carbon monoxide (CO) and nitrogen oxides (NOX), into harmless carbon dioxide (CO2) and water.

Check Engine Light
The result of OBD diagnostic trouble codes. When the Check Engine Light comes on, also known as the Malfunction Indicator Lamp, you have problems with your car’s emission control system recorded in your car’s on-board diagnostic (OBD) computer as OBDII diagnostic trouble codes.

common diagnostic trouble codes (DTC)
Diagnostic codes often associated with OBDII emission test failures. OBDII diagnostic codes from bad catalytic converters are pretty high on the list, but diagnostic codes related to other systems may rank even higher. In particular, OBD diagnostic codes are common for problems with the evaporative emission system (EVAP), engine misfiring, and lean fuel mixture. Oxygen sensor system and exhaust gas recirculation OBD codes are also possible.

An on-board diagnostic car computer, or OBD. The on-board diagnostic computer turns on your Check Engine Light and sets diagnostic trouble codes for fixing problems with your car’s emission system.

Also known as: diagnostics, auto diagnostic, OBD

diagnostic code reader
The most basic auto diagnostic tool. The OBD diagnostic code reader is a less expensive tool with limited function that will read diagnostic trouble codes from your car’s OBD computer.

Also known as: diagnostic tool, auto diagnostic code reader, OBD diagnostic tool

diagnostic scan tool
The more advanced OBD diagnostic tool. The OBD diagnostic scan tool may cost several hundred dollars, and will give the user more information regarding the diagnostic trouble codes than will the simpler diagnostic code reader.

Also known as: diagnostic tool, auto diagnostic scan tool, OBD diagnostic scan tool

diagnostic tools
Tools for scanning the car’s OBD computer, or PCM, for auto diagnostic trouble codes and related information. Auto diagnostic tools include the more basic OBD diagnostic code reader, and the more advanced OBD diagnostic scan tool.

Also known as: OBD diagnostic tools, OBD diagnostics

diagnostic trouble codes (DTC)
Basic auto diagnostics information from your car’s on-board diagnostic (OBD) computer, or PCM. OBDII diagnostic trouble codes are five-digit codes specifying problems related to smog control.  For example, OBD diagnostic codes related to your car’s powertrain run between P0100 and P1899, and codes related to the auto body or auto chassis start with ‘B’ and ‘C’ respectively. The third digit of the OBD code specifies the major area of problem; for example ‘1’ points to a problem with fuel or air, and ‘2’ to the injector circuit. OBD diagnostic trouble codes come in two major types: generic diagnostic codes, and enhanced diagnostic codes (OEM diagnostic codes). It’s important to realize that by itself, the diagnostic trouble code (DTC) does NOT tell you exactly what needs to be done: determining why the diagnostic code is there or the exact cause of the failure may be harder.

Also known as: diagnostic codes, auto diagnostic codes, OBD codes, OBDII codes

enhanced diagnostic trouble codes
OBD diagnostic codes that are specific to a particular car manufacturer, as opposed to generic diagnostic codes which apply to all automotive makes. Enhanced OBD diagnostic codes are also known as OEM (original equipment manufacturer) diagnostic codes, and cover nonemission diagnostic problems.

Also known as: enhanced OBD diagnostic codes, OEM OBD diagnostic codes

evaporative emission control system (EVAP) failure
One of the most common reasons for OBD diagnostic trouble codes and emission test failures, perhaps accounting for nearly 25%. The EVAP system keeps raw gas vapors from getting into the air. The most common reason for one OBD EVAP diagnostic code is having a loose fuel tank cap (gas cap) or a missing gas cap. Other EVAP problems that result in OBD EVAP diagnostic codes are broken or loose gas tank hoses, or a leaky charcoal cannister for capturing gas vapors.

Also known as: diagnostic code, OBDII diagnostic code, OBD2 diagnostic code

exhaust gas recirculation system (EGR) failure
A source of OBDII diagnostic codes and emission failures. The EGR sends exhaust back to the intake manifold for the purpose of lowering NOX air pollution.

Also known as: diagnostic code, OBDII diagnostic code, OBD2 diagnostic code

generic diagnostic trouble codes
OBD generic diagnostic codes are those that cover all automotive makes, rather than being specific to a particular make; diagnostic codes specific to a make are known instead as enhanced OBD diagnostic codes or OEM codes.

Also known as: generic OBD diagnostic codes, generic diagnostic code

malfunction indicator lamp
The warning light that comes on as a result of emission problems recorded as OBD diagnostic trouble codes. When the Malfunction Indicator Lamp comes on, which you see as the Check Engine Light, you have emission trouble, with OBDII diagnostic trouble codes recorded in your car’s on-board diagnostic computer (OBD).

OBD (on-board diagnostic)
The diagnostic trouble codes in your on-board diagnostic (OBD) vehicle computer. The OBD diagnostic codes are primarily for identifying emission problems, but there are some nonemission OBD diagnostic codes as well.

Also known as: diagnostic, auto diagnostic, OBDII, OBD2, OBD II, OBD 2

OBDII (on-board diagnostic)
The current standardized version of diagnostic trouble code information for emission problems and some nonemission issues. Beginning in 1994 and especially in 1996, OBDII replaced the earlier OBD system on newly manufactured cars.

Also known as: diagnostic, auto diagnostic, OBDII, OBD2, OBD II, OBD 2

powertrain contol module (PCM)
The car’s on-board diagnostic computer or OBD. The PCM turns on the Check Engine Light and generates OBD diagnostic codes in response to auto emission problems.

Also known as: OBD computer

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Frequently Asked Questions
FAQ About Complete Automotive Diagnostics and Auto Troubleshooting Services

Q: Why choose a Diamond Certified auto diagnostics shop?
A: Diamond Certified ends the guessing game by offering the auto diagnostics customer a choice of top-rated shop’s who pass the most in-depth rating process. Most companies can’t pass such a high standard, which means only local auto diagnostics shops rated Highest in Quality earn the Diamond Certified award. American Ratings Corporation also looks at every Diamond Certified company with in-depth and ongoing research and ratings. And your auto diagnostics service purchase is always backed up by the Diamond Certified Performance Guarantee. So you’re able to feel confident about having chosen a Diamond Certified auto diagnostics shop for your needs.

Q: What are my rights as an auto diagnostics customer in Alameda County?
A: Since 1974, the Automotive Repair Act has ensured your right to an estimate in advance on automotive diagnostic work, and to a list of charges when the OBD diagnostic service and associated repair or replacement work if any is finished. More information on your rights can be found at the California Bureau of Automotive Repair (BAR) (http://www.autorepair.ca.gov/).

Q: What are auto diagnostics?
A: Auto diagnostics may be thought of as on-board diagnostics (OBD), the on-board computer in your car that records a diagnostic trouble code indicating an emission problem (or maybe a nonemission problem) and turns on your Check Engine Light.

Q: What is the benefit of OBD (on-board diagnostics)?
A: On-board diagnostics (OBD) is a combination of sensors and computer hardware and software that checks cars for emission problems. Cars made in about 1988 began having OBD (on-board diagnostics) which became known as OBDI. Beginning with the manufacture of cars in 1994 and especially 1996, the original on-board diagnostics sytem was replaced in new cars by OBDII, also known as OBD2. OBDII turns on your car’s malfunction indicator, or Check Engine Light, in response to smog control issues. OBDII can spot minor problems with the car and may prevent them from causing big repair expenses. OBDII may also detect problems that are causing extra gas costs.

Q: Why is my OBD Check Engine Light on?
A: In essence, it’s on because your on-board diagnostic (OBD) computer has detected that you have an OBDII emission problem that may make your vehicle’s smog production go 50% over the federal limit, even if the problem is not causing any driving problems that you can detect or causing other warning lights to come on.

Q: What is OBDII?
A: OBDII, variously known as OBD2, OBD II, and OBD 2, means the second version of on-board auto diagnostics. OBDII is the version of OBD found in all automobiles since at least 1996. OBDII replaced OBDI to bring standardization to OBD emission control, and to expand OBD emission control.

Q: So why exactly is OBDII turning on my Check Engine Light?
A: OBDII is constantly checking different smog-related diagnostic information. OBDII looks at your catalytic converter, your fuel mixture, the firing of your engine, and emission control systems like the evaporative emissions system (EVAP) and the exhaust gas recycling system (EGR). OBDII is watching everything that can affect emissions, and sending out diagnostic trouble codes (DTC) to the computer, detecting even a loose or missing gas cap.

Q: Is it safe to drive my vehicle with the OBD Check Engine Light on?
A: The Check Engine Light is largely about OBDII diagnostic information for smog control purposes. The Check Engine Light OBDII diagnostic is glaringly nonspecific: you don’t know if you have a serious auto problem or not until a diagnostic scan is done and a systematic diagnostic evaluation is carried out to follow up the OBD diagnostic trouble code (DTC) discovered. You may not be able to tell that your car is driving any differently. You should always keep track of unusual signs like diagnostic noises, and should certainly be very aware of any other warning lights coming on that could be diagnostic for problems like oil or temperature trouble. But the Check Engine Light by itself may not indicate a drivability problem. It may be an OBDII problem as minor as not having had your gas cap twisted tightly enough (make sure you hear the gas cap click five times when you retighten it). The Check Engine Light does indicate an OBDII diagnostic smog control problem of some sort however, and eventually you will need to deal with it on your own or through a technician you can trust.

Q: How much does it cost to have my OBDII diagnostic trouble code (DTC) read?
A: Good news: some auto parts stores may do diagnostic scanning for free. It’s certainly worth checking, and beats paying $90 or more at a dealership to be told to be sure you tighten your gas cap.

Q: What does it mean when my OBD Check Engine Light comes on?
A: It means your OBD (on-board diagnostic) computer system has detected a problem of some sort that could increase air pollution to increase, use extra gas, or cause engine trouble. Examples of OBD problems that waste gas and harm the environment are missing or loose fuel caps. An example of an OBD problem that could cause engine damage is a misfiring engine.

Q: What does it mean if my OBD Check Engine Light goes off?
A: It means that your OBD (on-board diagnostic) computer system has confirmed that the emission trouble causing the OBDII diagnostic trouble code, maybe an untighted fuel cap or a spark plug fouling, has been fixed. You don’t need to worry further about a diagnostic emissions problem unless the OBD warning comes back on.

Q: What does it mean when my OBD Check Engine Light stays on?
A: It means your OBD (on-board diagnostic) computer system is warning you to find out if something is wrong fairly soon. When you stop, see if your gas cap is tightened down; a loose cap or a missing one can make your auto diagnostic system light come on. Remember when you get gas to always be sure your engine is not running, and to make sure your key is in the off position; not doing these things can turn on the OBDII diagnostic light. If the OBD Check Engine Light stays on after more trips, make plans to find out what the problem is using a diagnostic tool, or find a qualified diagnostic technician to get to the bottom of the problem.

Q: What does it mean when my OBD Check Engine Light flashes on and off?
A: A blinking OBD Check Engine Light is cause for concern. Your OBDII diagnostic system has spotted a severe problem, such as misfiring that could damage your catalytic converter. You can probably still drive the car without serious trouble, but you should not use it as much as otherwise, and should not use it at high speeds or with heavy loads until you can have the OBDII diagnostic trouble code taken care of.

Q: What will the OBDII technician do to take care of the OBD Check Engine Light problem?
A: The auto diagnostics technician will connect a scan tool to your vehicle’s OBD computer memory. The scan tool will pull OBDII diagnostic trouble codes and related diagnostic information that the technician can use for the full diagnostic process necessary to pinpoint the exact trouble with your car.

Q: Will repair for the OBDII diagnostic trouble code be covered by the warranty on my car?
A: It very well might be. Warranties vary with the auto part that has caused the OBDII diagnostic failure and with the make of the car. Keep in mind that responding quickly to the OBD diagnostic failure may lower your cost. The Clean Air Act requires a warranty of 8 years or 80,000 miles on big emissions control parts like the catalytic converter, which may cause OBD failures, and requires warranties of 2 years or 24,000 miles on smaller items.

Q: What’s the best way to find a good auto diagnostics shop or technician?
A: Remember the quality that Diamond Certified auto diagnostics shops offer.  Diamond Certified auto diagnostics shops offer value that may be unmatched by other locations. Diamond Certified shops have certified technicians, many prequalifications, numerous random consumer references, and a great guarantee.

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