On vehicles equipped with a dual clutch type transmissions, the computer reads data from a number of sensors in order to create a shifting strategy that matches the driving style of the owner. If the ECU can no longer determine an appropriate shifting strategy, a P2789 DTC will be set.
How Serious is the Code?
The P2789 diagnostic trouble code is relatively serious, and can often be accompanied by a number of other DTC’s that may shed light on the problem. The transmission problems associated with a P2789 DTC can often impact the drivability of the vehicle, and cause premature wear on the internal transmission parts.
Symptoms of a P2789 include:
- Harsh and/or delayed shifts
- Failed gear engagement
- Engine stalling
- Transmission overheating
- Low and/or dirty transmission fluid
- Clutch failure
- Failed pressure control solenoid
- Valve body issues
- Failed TCM
How to Diagnose the Code?
When trying to diagnose a P2789 OBDII trouble code, the first step should be to check the condition and level of the transmission fluid. The wiring and connectors on the transmission wiring harness will also need to be checked for signs of damage and corrosion. After that, the sensors, actuators and solenoids may need to be tested.
What Repairs Will Fix P2789?
- Change transmission fluid / filter
- Replace pressure control solenoid(s)
- Repair/replace valve body
- Replace TCM