Every time you turn your ignition switch on, the TCM does a self test to make sure that there’s enough battery voltage to power it. If there is not, a P0885 DTC will be saved.
How Serious is the Code?
The P0885 diagnostic trouble code is pretty serious, because it means there is not enough power to operate the transmission control module. When this happens, you will experience a erratic transmission behavior and possibly engine stalling.
Symptoms of a P0885 include:
- Rough shifts
- Delayed or erratic gear changes
- Unexpected engine stalling
- Shift interlock failure
- Malfunctioning speedometer
- The power relay for the TCM has failed
- Bad fuse
- Faulty fusible link
- Broken or corroded connectors
- Shorted wiring
- ECU programming/function problem
How to Diagnose the Code?
Since the P0885 OBDII trouble code is primarily electrical, the diagnosis should start with checking the battery voltage to make sure that it is working as it should. Next, check all of the fuses, relays and fusible links between the battery and the TCM. If everything looks good, the wiring and connectors will need to be checked for damage, corrosion and broken pins. If the voltage is present at the TCM power relay connector, the problem could be with the ECU or its programming. If there is no voltage, then there is an open circuit between the ECU and the TCM.
What Repairs Will Fix P0885?
- Repair or replace damaged wiring/connectors
- Replace the power relay
- Replace the blown fuse(s)
- Replace the fusible link
- Reprogram or replace the ECU
- P0700 – Transmission Control System Malfunction
- P0701 – Transmission Control System Range/Performance
- P0702 – Transmission Control System Electrical
- P0800 – TCM Power Input Signal Malfunction