Diagnostic mode 3: Check DTC Memory
Function
This diagnostic mode indicates all stored DTCs of components and systems which are emission relevant.
Malfunction Indicator Lamp (MIL) in instrument cluster lights up for one DTC entry. Refer to Malfunction Indicator Lamp (MIL) in instrument cluster
SAE Diagnostic Trouble Codes (DTCs)
The DTC always consists of a 5-digit alpha-numeric value with the following meaning:
| Component group: | |||||||
| P x x x x | DTC for drivetrain | ||||||
| U x x x x | DTC for network communication | ||||||
| Norm-Code: | |||||||
| P 0 x x x | DTCs defined by SAE with specified malfunction texts | ||||||
| U 0 x x x | |||||||
| P 1 x x x | Additional emission relevant DTCs provided by manufacturer | ||||||
| U 1 x x x | |||||||
| P 2 x x x | DTCs defined by SAE with specified malfunction texts | ||||||
| U 2 x x x | Additional emission relevant DTCs provided by manufacturer | ||||||
| P 3 x x x | Additional emission relevant DTCs provided by manufacturer | ||||||
| U 3 x x x | |||||||
| System group: | |||||||
| P x 0 x x | Fuel and air mixture and additional emission regulations | ||||||
| U x 0 x x | Network, electrical | ||||||
| P x 1 x x | Fuel and air ratios | ||||||
| U x 1 x x | Network, communication | ||||||
| System group: | |||||||
| P x 2 x x | Fuel and air ratios | ||||||
| U x 2 x x | Network, communication | ||||||
| P x 3 x x | Ignition system | ||||||
| U x 3 x x | Network, software | ||||||
| P x 4 x x | Additional exhaust regulation | ||||||
| U x 4 x x | Network, data | ||||||
| P x 5 x x | Speed and idle control | ||||||
| P x 6 x x | Control module and output signals | ||||||
| P x 7 x x | Transmission | ||||||
| P x 8 x x | Transmission | ||||||
| P x 9 x x | Control modules, input and output signals | ||||||
Work procedure
- Connect diagnostic tester. Refer to Diagnostic tester, connecting
- Start engine and let run at idle.
NOTE:
Only if engine does not start:
- Operate starter for approx. 6 seconds. Do not switch ignition off afterward.
- Under address word 33, select "Diagnostic mode 3: Check DTC memory."
The number of stored malfunctions or "0 malfunctions detected" is displayed.
- End diagnosis and switch ignition off.
- Repair stored malfunctions according to DTC table:
- SAE P0xxx-DTCs. Refer to SAE P0xxx-DTCs
- SAE P1xxx-DTCs. Refer to SAE P1xxx-DTCs
- SAE P2xxx-DTCs. Refer to SAE P2xxx-DTCs
- SAE U0xxx-DTCs. Refer to SAE U0xxx-DTCs
NOTE:
- The DTC table is sorted by SAE codes.
- "Emission"-relevant malfunctions are indicated in the instrument cluster via the Malfunction Indicator Lamp (MIL). Refer to Malfunction Indicator Lamp (MIL) in instrument cluster
- In Diagnostic mode 2, it can be determined at which operating condition a malfunction was detected and stored by the Engine Control Modules (ECMs). Refer to Diagnostic mode 2: Check operating conditions
- Erase DTC memory after repairing malfunction. Refer to Diagnostic mode 4: Reset/erase diagnostic data
Display example:
P0183 Fuel Temperature Sensor -G81- Open circuit/short circuit to B+
Explanation:
- P0183 = SAE diagnostic trouble code (malfunction identification number).
- Fuel Temperature Sensor -G81- = faulty circuit or malfunctioning component.
- Open circuit/short circuit to B+ = malfunction type as text