The hydraulic pressure sensor circuit relays information about the available hydraulic pressure inside of the transmission, back to the ECU. This helps the vehicle’s computer to make adjustments to the transmission gearing based on the current engine load and driving conditions. If the ECU detects a low voltage signal coming from the this transmission line pressure sensor circuit, a P0934 DTC will be set.
How Serious is the Code?
The P0934 diagnostic trouble code is very serious, because it means the ECU does not know how much hydraulic pressure is built up inside the transmission. This can lead to a number of drivability issues that include unusually hard shifts and higher gears being locked out.
Symptoms of a P0934 include:
- Harsh shifting at low RPMs
- Soft shifting when the RPMs increase
- Lower acceleration power than usual (because the ECU tells the transmission to start in a higher gear)
- The engine revs higher at speed (if the ECU has told the transmission into not shift into higher gears)
- Damage to the wiring or connectors
- Non-working fuses
- Defective transmission pressure sensor
- ECU/TCM issues
How to Diagnose the Code?
The first step to diagnosing a P0934 OBDII trouble code, is to check all of the wiring, grounds and connectors along the transmission pressure sensor circuit. Any related fuses or relays should also be tested. Should no issues be found, then the hydraulic pressure sensor itself will need to be tested. In rare cases, the ECU/TCM may actually be to blame.
What Repairs Will Fix P0934?
- Replace or repair damaged wiring or connectors
- Replace blown fuses
- Replace transmission pressure sensor
- Replace or reprogram ECU or TCM
- P0932 – Hydraulic Pressure Sensor Circuit
- P0933 – Hydraulic Pressure Sensor Range/Performance
- P0935 – Hydraulic Pressure Sensor Circuit High
- P0936 – Hydraulic Pressure Sensor Circuit Intermittent