P0945 code meaning
Hydraulic Pump Relay/Control Circuit/Open
Powertrain system Generic code P09xx codes Check engine light
What P0945 means
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.
P0945 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium, DIY possible
- Typical labor0.5 to 3 hours
- Clears after repairWhen cleared with a scanner
Symptoms of P0945
- Warning light on
- Pump does not run, pressure is not built
- Gears cannot be changed or auto stop-start disabled
Common causes of P0945
- Most likelyPump relay coil open or relay not seated
- PossibleOpen control wire or loose terminal between module and relay
- Less likelyFailed output stage in the control module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Hydraulic pump relayWiring harnessTCM
What each part of P0945 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 9 | Area: transmission. |
| 45 | The exact fault in that area. |
What to do next
- Note P0945 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0945
What does P0945 mean?
P0945 means "Hydraulic Pump Relay/Control Circuit/Open". The control module drives the motor of the hydraulic pump through a relay or a direct output. It is a generic code, so it means the same on every make.
Is it safe to drive with P0945?
Drive gently and only to a workshop. With P0945 the car can go into limp mode (reduced power) to protect itself.
Will P0945 fail an emissions test?
Yes, it can. P0945 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0945 to fix?
Difficulty: medium. A typical repair takes 0.5 to 3 hours of work. A careful DIY repair is possible with basic tools and a scanner.
Will P0945 clear itself after the repair?
Clear the code with a scanner after the repair. If the fault is fixed, it does not come back.