A transmission fluid pressure sensor monitors the hydraulic pressure inside the gearbox, so the ECU can decide on an appropriate shift strategy. If there is a little voltage situation on this switch’s circuit, a P0842 DTC will be set.
How Serious is the Code?
A P0842 diagnostic trouble code one of the more serious OBDII codes, as it relates to the hydraulic pressure needed to operate the transmission. Some of the transmission problems associated with this DTC include harsh or delayed shifts, transmission overheating and torque converter problems.
Symptoms of a P0842 include:
- Erratic, delayed or harsh shifts
- Torque converter clutch may not work
- Transmission not able to shift gears
- Transmission overheating
- Reduced fuel economy
- Low transmission fluid
- Dirty transmission fluid / filter
- Transmission fluid leak
- Frayed wiring / damaged connectors
- Failing transmission pump
- Failing transmission fluid pressure sensor
- Malfunctioning torque convertor
- Faulty pressure control solenoid
- Faulty pressure regulator
- Internal pressure problems
- Valve body issue
- TCM failure
How to Diagnose the Code?
Diagnosing a P0842 OBDII trouble code should begin with a check of the transmission fluid. If it is too low or dirty, hydraulic pressure will be affected. Frayed wires or damaged connectors along the transmission wiring harness also need to be addressed, along with any transmission fluid leaks. If the source of the problem has not been located, further mechanical diagnosis may be needed.
What Repairs Will Fix P0842?
- 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