The upshift switch allows you to manually upshift your transmission by tapping the gear selector or using the paddle shifters behind the steering wheel. If the ECU determines that the circuit on which the upshift switch operates is having an intermittent problem, a P2778 DTC will be saved.
How Serious is the Code?
The P2778 diagnostic trouble code probably will not affect the drivability of your vehicle. However, you likely will not be able to control the upshift function of your transmission manually.
Symptoms of a P2778 include:
- Unable to shift with paddle shifters/manual shift gate
- Broken upshift switch
- Wiring issue
- Shifter assembly failure
- ECU programming issue
How to Diagnose the Code?
In order to diagnose a P2778 OBDII trouble code, your mechanic should carefully inspect the wiring and connectors going to the shifter assembly. They should also check to see if there are any manufacturer TSB’s related to the problem. If nothing is found, the upshift switch and shifter assembly should be checked.
What Repairs Will Fix P2778?
- Replace upshift switch
- Repair wiring/connectors
- Repair/replace shifter assembly
- Reflash/update ECU programming