P1778: Transmission Reverse I/P Circuit Malfunction
HighPowertrainTransmission
What does P1778 mean?
P1778 is a diagnostic trouble code indicating "Transmission Reverse I/P Circuit Malfunction". A component in the transmission has been flagged as malfunctioning by the vehicle's ECU. This requires diagnosis to determine whether the part itself has failed or if there is a related wiring or control issue.
Common causes
- Low or degraded transmission fluid
- Worn clutch packs or bands
- Faulty shift solenoid
- Wiring issue to the transmission control module
- Failing torque converter
What should you do?
This is a significant issue that should be diagnosed and repaired soon. Avoid long trips or heavy driving until the problem is resolved. Continued driving may cause additional damage.
Get a diagnosis for YOUR car
Code P1778 can mean different things depending on your vehicle. TorqueBot gives you a diagnosis specific to your make, model, and year.