An upshift switch allows you to manually upshift the transmission using either the shift lever or paddle shifters behind the steering wheel. If the voltage signal coming from the upshift switch is too high, a P2777 DTC will be stored.
How Serious is the Code?
A P2777 diagnostic trouble code is not really going to affect the drivability of your vehicle. However, you probably will not be able to manually upshift your transmission.
Symptoms of a P2777 include:
- Shifting with paddle shifters/manual shift gate will be disabled
- Failed upshift switch
- Wiring issue
- Shifter assembly failure
- ECU programming issue
How to Diagnose the Code?
In order to diagnose a P2777 OBDII trouble code a mechanic will need to promptly inspect all of the wiring and connectors, going to the shifter assembly. The manufacturer’s TSB database will also need to be checked, to see if there are any known solutions for this problem. If no issues are found, then the upshift switch will need to be checked, along with possibly the shifter assembly.
What Repairs Will Fix P2777?
- Replace upshift switch
- Repair wiring/connectors
- Repair/replace shifter assembly
- Reflash/update ECU programming