When you start your vehicle, a little electrical device known as the transmission control relay, comes to life and sends electricity down to the transmission control solenoids (this basically allows your transmission to function). If there is a low voltage signal connected on the power relay sense circuit, a P0890 DTC will be saved.
How Serious is the Code?
The P0890 diagnostic trouble code gets triggered when the transmission solenoids are basically not “powering up”. This means your transmission will not be able to shift gears, and will likely go into Limp Mode to protect itself from further damage.
Symptoms of a P0890 include:
- Limp mode
- Transmission does not shift
- Damage to the wiring and/or connectors
- Faulty wiring transmission control relay
- ECU or TCM programming problems
How to Diagnose the Code?
The first step to diagnosing a P0890 OBDII trouble code, is to check the transmission control relay and any related fuses. If no problems are found, then any related wires and connectors should be carefully inspected. If no problems are found up to this point, then it’s possible that the TCM is not sending power to the TCR, which could be caused by a software issue or an internal failure of the TCM.
What Repairs Will Fix P0890?
- Repair or replace damaged wiring and/or connectors
- Replace transmission control relay
- Update ECU or TCM software