Car Diagnostic Codes List

If you own a car, then you know how important it is to know how to read car diagnostic codes before you take it to the mechanic or fixing.

Diagnostic trouble/fault/error codes are codes that are kept by the on-board computer diagnostic system. These are kept in response to a problem found in the vehicle by the system. These codes are kept hen a sensor in the vehicle reports a reading that is outside the normal/accepted range. Usually, these DTC’s detect a certain problem area and are intended to offer the technician with a guide as to where an error might be taking place within the car.



When checking diagnostic trouble codes, you shouldn’t just use reference through DTC, but as well the vehicle service manual and other much needed examining. This will make you to avoid unplanned hazards when repairing a car based on its DTC codes. Also, you should utilize a reliable OBDII code reader.

Complete Car Diagnostic Codes List

To describe the standard trouble OBD codes by family, it can be outlined as follow:

For instance; P0301 – P is for powertrain, c for chassis, B for body, U for user network, and first digit shows if it is generic – 0 or manufacturer – 1. Since the list of generic OBD codes is not always enough, manufacturers can add as many of their own codes as they require. As a matter of fact, the final 3 digits correspond to an incriminated number.
0, 1, and 2: for the air/fuel mixture
3: for the ignition system
4: for inspecting auxiliary emissions
5: for engine idling
6: for the onboard computer and ancillary outputs
7, 8 and 9: for the transmission (gearbox)
A, B, and C: for hybrid propulsion

Generic VS Manufacturer specific codes

It is easier for a motorist to differentiate between generic and manufacturer specific codes. Generic, usually abbreviated as “P0xxx” is defined in the E0BD/OBDII standard and will be the same for all manufacturers. While on the other hand, manufacturer specific normally abbreviated as “P1xxx” is a code added by the manufacturer where they feel that the code is not present in the generic list. The definitions are as a result set by the manufacturer.

To sum up, codes that start with P0 are generic codes, while those that start with P1 are manufacturer-specific codes. Extra codes groups are present to enable expansion of these code lists. The complete breakdown of the code groups is as follows:

Powertrain codes

P0xxx – Generic
P1xxx – Manufacturer-specific
P2xxx – Generic
P30xx-P33xx – Manufacturer-specific
P34xx-P39xx – Generic

Chassis codes

COxxx – Generic
C1xxx – Manufacturer-specific
C2xxx – Manufacturer-specific
C3xxx – Generic

Body codes

B0xxx – Generic
B1xxx – Manufacturer-specific
B2xxx – Manufacturer-specific
B3xxx – Generic

Network communication codes

U0xxx – Generic
U1xxx – Manufacturer-specific
U2xxx – Manufacturer-specific
U3xxx – Generic



These are some of the normal car diagnostic codes that you are likely to find on most vehicles. There are more than 5, 000 codes that are commonly used. OBD codes were standardized using SAE J2012 and ISO 15031-6 standards. All you have to do is to search for a software and download all the 5000 plus codes.