Transmission fluid is what moves the parts inside the gearbox, thanks to the hydraulic pressure created by the engine. If the ECU thinks the transmission fluid pressure is too high, it will save a DTC P0869.
How severe is the code?
Having a diagnostic code P0869 is very serious, as it can affect both the driving of your vehicle and severely damage the internal parts of the transmission. Needless to say, a mechanic should diagnose the problem immediately.
Symptoms
Symptoms of a P0869 include:
- Transmission overheating
- Smoke / odor coming from the transmission
- Transmission slipping
- The transmission does not engage gears
Causes
- Low or dirty transmission fluid
- Transmission fluid leaks
- Damaged connectors and/or wiring
- Overheated transmission
- Overheated engine
- Faulty transmission pump
- Faulty transmission fluid pressure sensor
- Faulty transmission fluid temperature sensor
How to diagnose the code?
Dirty or low transmission fluid is one of the main causes of an OBDII P0869 fault code. Transmission fluid leaks can also cause this OBD2 error code, as can damaged wiring and broken connectors. The transmission fluid pressure sensor and the transmission fluid temperature sensor may also need to be checked. If none of these transmission issues are present, a thorough internal diagnosis will be necessary to determine if the problem comes from the transmission pump or another mechanical part.
What repairs will fix P0869?
- 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 the transmission fluid pressure sensor
- Replace the transmission fluid temperature sensor
- Replace or repair the transmission