P0942 Hydraulic Pressure Unit

P0942 indicates a hydraulic pressure unit fault. The pressure-generating unit or its control feedback is not matching the controller's expected behavior.

Code details

Generic OBD-II · P0

System: Transmission
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not replace the pressure unit before confirming pump command, pressure feedback, relay operation, and supply voltage.

Symptoms of P0942

Harsh, delayed, or slipping shifts, or being stuck in one gear.
Check-engine light, sometimes with limp-home mode.
Flaring RPM or a shudder under load.

Common causes of P0942

Low or degraded transmission fluid.
A failing speed sensor, shift solenoid, or pressure-control circuit.
Wiring, connector, or internal hydraulic/mechanical faults.

Useful checks before replacing parts

Compare pressure unit command, pump relay activity, pressure sensor data, current draw, cycling frequency, and hydraulic temperature.
Inspect fluid level and condition, pump operation, relay circuit, accumulator or pressure unit leaks, wiring, and connector condition.
Review whether the fault appears during pressure build, gear selection, actuator movement, or after long idle periods.

Related OBD-II codes

These nearby transmission entries can help compare wording and pin down the fault area.