The control module drives the motor of the hydraulic pump through a relay or a direct output. This code reports a general circuit fault or an open in that control path, so the pump cannot be switched reliably. No manufacturer documents this exact code publicly. The layout is shown by a ZF patent for an automated gearbox, in which a motor-driven pump draws oil from a reservoir and charges a pressure accumulator behind a one-way valve, with shut-off valves feeding the shift cylinders. CARB requires circuit checks on transmission outputs. P0946 is the plausibility fault, P0947 and P0948 low and high; P094E covers the pump supply instead of the control side. Without the pump the gearbox soon runs out of pressure.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Warning light on
- Pump does not run, pressure is not built
- Gears cannot be changed or auto stop-start disabled
Most likely causes
- Pump relay coil open or relay not seated
- Open control wire or loose terminal between module and relay
- Failed output stage in the control module
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P0945 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 9: Transmission
- 45: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0945?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P0945?
The most common causes are: pump relay coil open or relay not seated; open control wire or loose terminal between module and relay; failed output stage in the control module.
Related codes
- P0946Hydraulic Pump Relay/Control Circuit Range/Performance
- P0947Hydraulic Pump Relay/Control Circuit Low
- P0948Hydraulic Pump Relay/Control Circuit High
- P094EHydraulic Pump Supply Voltage Circuit/Open
- P0942Hydraulic Pressure Unit
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.