Diagnostic Trouble Code
P0885
TCM Power Relay Control Circuit /Open
Technical Description P0885
TCM Power Relay Control Circuit /Open
Severity Level P0885
Battery voltage is supplied to the TCM using one (or more) fuses and/or contact relays. If the TCM or PCM detect insufficient voltage on the input supply (from the relay or fuse) a P0885 will be stored and a MIL illuminated.
If this code is stored, you may have noticed that your transmission shifts much more harshly than normal. If your vehicle has exhibited a code P0865, it should be diagnosed as soon as possible.
Symptoms P0885
1
Electronic traction control disabled
2
Erratic transmission shift patterns
3
Failure of the transmission to shift
4
Other related codes
5
ABS disabled
Possible Causes P0885
1
Bad relay or blown fuse (fusible link)
2
Vehicle speed sensor failure
3
Open or shorted circuits in the CAN
4
Mechanical transmission failure
5
Defective TCM, PCM, or programming error
Solutions & Repair Steps P0885
You will need a diagnostic scanner, a digital volt/ohmmeter (DVOM), and a source of reliable vehicle information in order to accurately diagnose a code P0885. An oscilloscope can also prove very helpful in diagnosing various speed sensors.
You may save yourself time by searching for technical service bulletins (TSB) that replicate the code stored, vehicle (year, make, model, and engine), and symptoms exhibited. This information may be found in your vehicle information source. If you find the right TSB, it could yield a speedy solution to your diagnosis.
After you connect the scanner to the vehicle diagnostic port and retrieve all stored codes and pertinent freeze frame data, write the information down (in case the code proves to be an intermittent one). After that, clear the codes and test drive the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.
The code may be more difficult to diagnose if the PCM enters readiness mode at this point, because the code is intermittent. The condition which caused the P0885 to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, continue with the diagnosis.
You may obtain connector face views, connector pinout charts, component locator charts, wiring diagrams, and diagnostic flow charts (pertaining to the code and vehicle in question) using your source of vehicle information.
Perform a visual inspection of related wiring and connectors. Repair or replace wiring that has been cut, burned, or damaged.
Use the DVOM to test voltage and ground circuits at the TCM and/or PCM. If no voltage is detected, check the system relay and related fuses. Replace defective relays and/or blown (or otherwise defective) fuses as required.
If voltage and ground are detected at the TCM, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the component in question and the PCM. If voltage is discovered there, suspect a defective TCM. PCM, or a programming error.
You may save yourself time by searching for technical service bulletins (TSB) that replicate the code stored, vehicle (year, make, model, and engine), and symptoms exhibited. This information may be found in your vehicle information source. If you find the right TSB, it could yield a speedy solution to your diagnosis.
After you connect the scanner to the vehicle diagnostic port and retrieve all stored codes and pertinent freeze frame data, write the information down (in case the code proves to be an intermittent one). After that, clear the codes and test drive the vehicle until one of two things happens; the code is restored or the PCM enters readiness mode.
The code may be more difficult to diagnose if the PCM enters readiness mode at this point, because the code is intermittent. The condition which caused the P0885 to be stored may need to worsen before an accurate diagnosis can be made. If the code is restored, continue with the diagnosis.
You may obtain connector face views, connector pinout charts, component locator charts, wiring diagrams, and diagnostic flow charts (pertaining to the code and vehicle in question) using your source of vehicle information.
Perform a visual inspection of related wiring and connectors. Repair or replace wiring that has been cut, burned, or damaged.
Use the DVOM to test voltage and ground circuits at the TCM and/or PCM. If no voltage is detected, check the system relay and related fuses. Replace defective relays and/or blown (or otherwise defective) fuses as required.
If voltage and ground are detected at the TCM, test the corresponding circuit at the PCM connector. If no voltage is detected there, suspect an open circuit between the component in question and the PCM. If voltage is discovered there, suspect a defective TCM. PCM, or a programming error.