When your transmission changes gears up or down, it is actually pressurized transmission fluid that makes things happen. This hydraulic pressure is constantly monitored by the transmission fluid pressure sensor, which then relays the information to the ECU through a series of electrical signals. If the computer detects that there is a low voltage signal coming from this sensor’s circuit, a P0877 DTC will be saved.
How Serious is the Code?
Although some transmission trouble codes are not that serious, a P0877 diagnostic trouble code actually is. This OBDII code can be caused by either an electrical malfunction or mechanical one. Needless to say, drivability issues will ensue, and the internal damage could be catastrophic.
Symptoms of a P0877 include:
- Transmission is overheating
- The transmission is slipping
- Transmission will not go into gear
- The transmission does not have enough fluid
- Transmission fluid and filter need to be changed
- Transmission fluid is leaking from a gasket or component
- Transmission overheating
- Engine overheating
- The wiring or connectors are damaged
- Transmission pump failure
- Transmission fluid pressure sensor failure
- Transmission fluid temperature sensor failure
- TCM failure
- Internal mechanical failure
How to Diagnose the Code?
Many times, car manufacturers are aware of common transmission problems, and issue repair guidance in a technical service bulletin (TSB). So the TSB database should be checked, along with the condition of the wiring and connectors on the transmission wiring harness. The transmission fluid pressure sensor will also need to be checked to make sure that it works. If no problems have been found, then suspect an internal mechanical failure like a malfunctioning transmission pump or valve body.
What Repairs Will Fix P0877?
- Change the transmission fluid and filter
- Repair transmission fluid leaks
- Repair or replace damaged wiring and sensors on the transmission wiring harness
- Replace the transmission pump
- Replace transmission fluid pressure sensor
- Replace transmission fluid temperature sensor
- Replace or repair valve body
- Replace or repair transmission