The transmission fluid pressure sensor is responsible for monitoring the pressure of the transmission fluid inside the gearbox, then relaying information to the ECU so it can set up the proper shift timing and engine calibrations. If the vehicle has a P0870 DTC, it means that there is either an electrical issue on the sensor’s, or there’s a mechanical failure inside the transmission.
How Serious is the Code?
The P0870 diagnostic trouble code is one of the more serious OBD2 codes, because you don’t know if it relates to a bad sensor, electrical problem or mechanical failure deep inside the transmission. Either way, you can experience serious drivability issues, and serious internal damage may also occur.
Symptoms of a P0870 include:
- Transmission overheating
- Slipping through the gears
- Transmission fails to engage gears
- Smoke coming from the transmission and transmission dipstick
- Low transmission fluid
- Dirty transmission fluid
- Transmission fluid leak
- Shorted/frayed wiring
- Broken or corroded connectors
- Overheated transmission
- Overheated engine
- Bad transmission pump
- Bad transmission fluid pressure sensor
- Bad transmission fluid temperature sensor
- Bad transmission control module
- Valve body problems
- Internal mechanical failure
How to Diagnose the Code?
If the transmission fluid is clean and there are no damage wires or connectors along the transmission wiring harness, then the transmission fluid pressure sensor itself will need to be checked. If it appears to be in good shape, to the valve body, transmission pump and other internal components will need to be inspected.
What Repairs Will Fix P0870?
- 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