Hydraulic Pump Relay/Control Circuit High
What it means
P0948 sets when the control circuit for the hydraulic pump relay reads an abnormally high voltage — typically an open circuit or a short to power. On dual-clutch and automated-manual gearboxes this electric pump supplies the pressure that operates the clutches and shifts, so a control-circuit fault can leave the transmission shifting harshly or dropping into a protective limp mode. The engine still starts and runs; the fault is in the pump relay's control wiring rather than the engine itself.
Can I keep driving? Driveable, but if the hydraulic pump can't run, clutch and shift control may fail, causing harsh shifts or limp mode; fix it promptly.
Common symptoms
What you'll notice
- Check-engine light on
- Hydraulic pump malfunction
- Harsh, erratic, or missed shifts
- Possible limp (fail-safe) mode
Common causes
Most likely first
- Open or short-to-voltage in the pump relay control circuitLikely
- Faulty hydraulic pump relayCommon
- Damaged or corroded wiring or connectorsCommon
- Faulty pump control module / TCMLess often
How to diagnose & fix
Work through it in order
- Confirm with companion codes (P0945-P0947).
- Inspect the pump relay control wiring for opens or a short to power.
- Test the hydraulic pump relay.
- Repair the wiring or replace the relay as needed.
- Clear the code and retest, verifying the pump actually runs.
FAQ
Quick answers
Is it safe to drive with P0948?+
Can I just clear P0948?+
Related codes
Often seen with P0948
Read & clear P0948 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.