ArtsAutosBooksBusinessEducationEntertainmentFamilyFashionFoodGamesGenderHealthHolidaysHomeHubPagesPersonal FinancePetsPoliticsReligionSportsTechnologyTravel

Understanding OBD-2 Engine Codes

Updated on February 5, 2013

Sooner or later, your engine light will be lit. The on board computer unit in your car has found something that is out of spec or not working via the many electronic sensors. Mechanical issues are usually not found unless there is a sensor for it.

When the engine light is lit, the only way to find out what is going on is to use a engine analyzer that plugs into the connector under the dash. There are many types, from very expensive ones to handheld ones that cost much less and provide a code readout of what was found. These are DTC or Diagnostic Trouble Codes. Most newer cars have the OBD-2 format now with universal DTC codes that provide a general problem area. They help pinpoint the general area where the issue is that triggered the engine light (known as the MIL, Malfunction Indicator Light).

The code structure provides the following info:

If Pxxxx = powertrain; Uxxxx = vehicle network communications; Bxxxx = body; Cxxxx = chassis

Most DTC codes start with P.

The second digit also provides info:

P0xxx = Government required codes; P1xxx = Manufacturer Codes

Many less expensive scanners will only report standardized P0 codes.

The third digit provides the following info:

Px1xx, Px2xx = air\fuel measurement; Px3xx = ignition; Px4xx = emission; Px5xx = speed and idle; Px6xx = computer output signal; Px7xx, Px8xx = transmission; Px9xx = control modules

The fourth and fifth digits actually pinpoint individual components causing a problem. However, they appear on the most expensive analyzers.

Cars have up to 3000 DTC type codes, some are universal to all cars, others are car specific. For instance, your engine light comes on, you take a scan with a handheld analyzer and come up with a P0172, this means a Fuel on bank 1 is too rich or a P0101, which indicates the MAF air flow meter is intermittently out of range.

Most DTC codes that appear are P0, that is, in the engine area and government standardized codes. The remaining digits are ID codes for various problems. They go from P0010 to P3211. Once you obtain a DTC code list in your car's service manual or online, you can get an idea what is wrong with your car.

Many places offer free handheld analyzer engine checks, otherwise, just hooking it up can cost $100.


    0 of 8192 characters used
    Post Comment

    No comments yet.


    This website uses cookies

    As a user in the EEA, your approval is needed on a few things. To provide a better website experience, uses cookies (and other similar technologies) and may collect, process, and share personal data. Please choose which areas of our service you consent to our doing so.

    For more information on managing or withdrawing consents and how we handle data, visit our Privacy Policy at:

    Show Details
    HubPages Device IDThis is used to identify particular browsers or devices when the access the service, and is used for security reasons.
    LoginThis is necessary to sign in to the HubPages Service.
    Google RecaptchaThis is used to prevent bots and spam. (Privacy Policy)
    AkismetThis is used to detect comment spam. (Privacy Policy)
    HubPages Google AnalyticsThis is used to provide data on traffic to our website, all personally identifyable data is anonymized. (Privacy Policy)
    HubPages Traffic PixelThis is used to collect data on traffic to articles and other pages on our site. Unless you are signed in to a HubPages account, all personally identifiable information is anonymized.
    Amazon Web ServicesThis is a cloud services platform that we used to host our service. (Privacy Policy)
    CloudflareThis is a cloud CDN service that we use to efficiently deliver files required for our service to operate such as javascript, cascading style sheets, images, and videos. (Privacy Policy)
    Google Hosted LibrariesJavascript software libraries such as jQuery are loaded at endpoints on the or domains, for performance and efficiency reasons. (Privacy Policy)
    Google Custom SearchThis is feature allows you to search the site. (Privacy Policy)
    Google MapsSome articles have Google Maps embedded in them. (Privacy Policy)
    Google ChartsThis is used to display charts and graphs on articles and the author center. (Privacy Policy)
    Google AdSense Host APIThis service allows you to sign up for or associate a Google AdSense account with HubPages, so that you can earn money from ads on your articles. No data is shared unless you engage with this feature. (Privacy Policy)
    Google YouTubeSome articles have YouTube videos embedded in them. (Privacy Policy)
    VimeoSome articles have Vimeo videos embedded in them. (Privacy Policy)
    PaypalThis is used for a registered author who enrolls in the HubPages Earnings program and requests to be paid via PayPal. No data is shared with Paypal unless you engage with this feature. (Privacy Policy)
    Facebook LoginYou can use this to streamline signing up for, or signing in to your Hubpages account. No data is shared with Facebook unless you engage with this feature. (Privacy Policy)
    MavenThis supports the Maven widget and search functionality. (Privacy Policy)
    Google AdSenseThis is an ad network. (Privacy Policy)
    Google DoubleClickGoogle provides ad serving technology and runs an ad network. (Privacy Policy)
    Index ExchangeThis is an ad network. (Privacy Policy)
    SovrnThis is an ad network. (Privacy Policy)
    Facebook AdsThis is an ad network. (Privacy Policy)
    Amazon Unified Ad MarketplaceThis is an ad network. (Privacy Policy)
    AppNexusThis is an ad network. (Privacy Policy)
    OpenxThis is an ad network. (Privacy Policy)
    Rubicon ProjectThis is an ad network. (Privacy Policy)
    TripleLiftThis is an ad network. (Privacy Policy)
    Say MediaWe partner with Say Media to deliver ad campaigns on our sites. (Privacy Policy)
    Remarketing PixelsWe may use remarketing pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to advertise the HubPages Service to people that have visited our sites.
    Conversion Tracking PixelsWe may use conversion tracking pixels from advertising networks such as Google AdWords, Bing Ads, and Facebook in order to identify when an advertisement has successfully resulted in the desired action, such as signing up for the HubPages Service or publishing an article on the HubPages Service.
    Author Google AnalyticsThis is used to provide traffic data and reports to the authors of articles on the HubPages Service. (Privacy Policy)
    ComscoreComScore is a media measurement and analytics company providing marketing data and analytics to enterprises, media and advertising agencies, and publishers. Non-consent will result in ComScore only processing obfuscated personal data. (Privacy Policy)
    Amazon Tracking PixelSome articles display amazon products as part of the Amazon Affiliate program, this pixel provides traffic statistics for those products (Privacy Policy)