Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Diagnostic Mode 04 - Erase DTC Memory
Diagnostic Mode 04 makes it possible to erase the DTC memory and to reset all emissions-related diagnostic data. In that way, all faults in the DTC memory in the ECM and TCM are erased. The adaptation values may also be reset.
Emissions-related diagnostic data includes (as applicable):
- -MIL Status
- -Number of DTCs
- -Readiness Bits
- -Confirmed DTCs
- -Pending DTCs
- -DTC that belongs to freeze frame
- -Freeze frame data
- -Test results of specific diagnostic functions
- -Distance driven with "MIL ON"
- -Number of Warm-Up Cycles after erasing the DTC memory
- -Distance driven after erasing the DTC memory
- -Misfire counter
Depending on scan tool and protocol used, the information displayed in diagnostic mode 04 may be referred to by different names such as Test-ID (CID), Hex-ID, Component-ID (CID), On-Board Diagnostic Monitor Identifier (OBDMID), or contain no name at all and be referenced by only a number.
Procedure
-- Connect the scan tool.
-- Switch the ignition on.
-- Select "Diagnostic Mode 03: Interrogating fault memory ".
-- Then select "Mode 4: Reset/delete diagnostic data".
The scan tool will display: "Diagnostic data are being erased".
-- Switch the ignition off.
-- End of diagnosis.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.