A transmission fluid pressure sensor tells the ECU how much hydraulic pressure is available, so it can determine the proper shifting strategy based on things like engine load and vehicle speed. If this sensor is not performing according to the preset parameters, a P0846 DTC will be set.
How Serious is the Code?
A P0846 diagnostic trouble code is very serious, and can lead to a number of transmission problems that can affect the drivability of your vehicle. These include failed gear engagement, transmission overheating and torque converter problems.
Symptoms of a P0846 include:
- Hard or erratic shifts
- Complete failure to shift
- Reduced fuel economy
- Non-working torque converter clutch
- Transmission overheating
- Gearbox too low on transmission fluid
- Transmission fluid is dirty
- Transmission fluid leak
- Wiring and/or connectors are damaged
- Transmission pump is malfunctioning
- Torque convertor problems
- Failing transmission fluid pressure sensor
- Failing pressure control solenoid
- Failing pressure regulator
- Hydraulic pressure problems
- Valve body problems
- TCM malfunctioning
How to Diagnose the Code?
The level and condition of the transmission fluid is one of first things that should be checked when trying to diagnose a P0846 OBDII trouble code. Metallic debris and sludge can impact both the hydraulic fluid pressure and the performance of the transmission fluid pressure sensor. The wiring and connectors can also cause problems, as can transmission fluid leaks. If no transmission problems have been found up to this point, then further mechanical diagnosis will be needed.
What Repairs Will Fix P0846?
- Change transmission fluid and filter
- Repair leaks
- Repair or replace damaged wiring and connectors
- Replace transmission fluid pressure sensor
- Repair or replace torque converter
- Repair or replace valve body
- Replace transmission pump
- Replace pressure control solenoid
- Replace pressure regulator
- Reprogram or replace TCM