P0948
PowertrainTransmission Pressurehigh severityHydraulic Pump Relay Circuit High
What P0948 Means
The voltage in the hydraulic pump relay circuit is higher than expected. This usually points to a short to power or an open in the control circuit.
Symptoms
- Transmission warning light on
- Erratic or harsh shifting
- Transmission may not engage
Common Causes
- Short to voltage in relay wiring
- Faulty pump relay
- Open control circuit
- Faulty PCM/TCM
Diagnostic Steps
- Inspect relay wiring for shorts to power
- Monitor circuit voltage with scan tool
- Test relay operation
- Verify PCM control and ground circuits
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