DTC - Diagnostic Trouble Codes
What are DTC codes?
- The SAE J2012 standard defines a 5-digit code in which each digit represents a predetermined value. All codes are presented in the same way for ease of use. Some of these are defined by this standard, and others are reserved for manufacturers.
- The code has the following format: YXXXX (ex. P0308)
- Where Y, the first digit, represents the function of the vehicle:
| Y digit | Function |
|---|---|
| P | Motor Electronics & Transmission (Powertrain) |
| B | Bodywork |
| C | Chassis |
| U | Undefined |
- The second digit indicates the organization responsible for defining the code:
| 2th digit | Organization responsible |
|---|---|
| 0 | SAE (code common to all brands) |
| 1 | The manufacturer of the vehicle (different code for different brands) |
- The third digit represents a specific function of the vehicle:
| 3th dígit | Function |
|---|---|
| 0 | The complete electronic system |
| 1 y 2 | Air and fuel control |
| 3 | Ignition system |
| 4 | Auxiliary emission control |
| 5 | Speed and idle speed control |
| 6 | ECU and inputs and outputs |
| 7 | Transmission |
- The fourth and fifth digits are specifically related to the fault.
- For example, code P0308 indicates a problem in the engine electronics (P), defined by SAE (0) and common to any vehicle, related to the ignition system (3) and failure in cylinder # 8 (08 ).
IMPORTANT
- There may be fault codes stored on the ECU that do not activate the MIL.
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