Diagnostic Mode 0A - Check Permanent DTC Memory
The following is a generic explanation of the requirements, coverage, and operation of Mode 0A.
Mode 0A may only be supported exclusively by OBD control modules in US vehicles. Mode 0A may not be supported in EOBD vehicles, meaning the control module may not send a response here.
Mode 0A - Check Permanent DTC Memory (Request emissions-related diagnostic trouble codes with permanent status after code clear)
Permanent Fault Codes From MY 2010 with Phase-In conforming to CCR 1968.2 (d) (2.2.5):
- 50% from MY 2010 / 75% from MY 2011 / 100% from MY 2012. The vehicle only participates in Phase-In if all of the OBD-relevant control modules in the vehicle meet these requirements.
Mode 0A enables the request of all OBD-relevant faults with the status "Permanent Fault Code":
- Permanent Fault Codes are Confirmed Fault Codes that are currently activating the MIL. That means faults that are still displayed in Mode 03 but no longer activate the MIL (History Fault Codes) are not Permanent Fault Codes.
- Permanent Fault Codes are updated in Mode 0A at the same time as NVRAM storage immediately after switching the ignition off. A newly detected Permanent Fault Code is only visible after switching the ignition off/on in Mode 0A.
- Permanent Fault Codes may only be erased in the control module after they are corrected as long as the last diagnostic result was a PASS and the MIL is no longer activated by this fault. The Permanent Fault Codes should be erased from Mode 0A at the same time the MIL switches off when the ignition is switched off/on.
- Permanent Fault Codes may not be erased by clearing the DTC memory or disconnecting the power supply. Storage in NVRAM is required.
- Permanent Fault Codes may only be erased after clearing the DTC memory under the following conditions:
- As long as no FAIL diagnostic result was detected for a Permanent Fault Code and at least one PASS diagnostic result was detected -and the Minimum Trip Conditions for a General Denominator (without considering high/ambient temperature) were met in this phase in any DCY after erasing the DTC memory.
The engine control module relays the message "Minimum Trip conditions met" to all other OBD control modules via CAN: CAN message OBD_01, Byte 8, Bit 4:
- OBD_Minimum_Trip -Permanent Fault Codes may NOT be erased if the diagnostic result is FAIL after clearing the DTC memory. A Pending Fault Code should be stored and the DTC memory line should be overwritten with new Freeze Frame data. (Exception: If the Pending Fault Code is corrected without a Confirmed Fault Code being detected, the Permanent Fault Code may also be erased under the conditions described below.)
- Permanent Fault Codes should be erased in engine control modules after Update Programming. At this time, all readiness bits (Mode 01 PID $01) must be reset to "not complete". Permanent Fault Codes should not be erased in OBD control modules with Comprehensive Components (CCM) as a single readiness bit if the identical program/data status is being programmed. If a different program/data status is being programmed, Permanent Fault Codes should be erased after Update Programming.
- The procedure in Mode 01 through Mode 09 and in the repair tester is NOT affected by implementation of the Permanent Fault Codes.
After MIL off during the 40 key cycle self-healing process, the fault may not be reported as Permanent Fault Code anymore
Procedure
- Erasing Permanent Fault Codes after code clear repair $0A - Permanent Fault Codes, can only be erased at the end of a driving cycle (during ECM keep alive time) if all the following conditions are fulfilled:
- Permanent Fault Codes after code clear, the vehicle needs to be driven!
- DTC cleared
- MONITORS: PASS
- Conditions fulfilled 600 s. (cumulative) Engine running
- DRIVE: 300 s (cumulative) vehicle speed > 25 mph (40 km/h)