P0945

Hydraulic Pump Relay/Control Circuit/Open

Q: Is it safe to drive with P0945?

Treat this as a stop-and-diagnose fault. Without the hydraulic pump the transmission can lose the pressure it needs to engage or shift, which risks leaving you stranded or damaging the gearbox.

Q: Can I just clear P0945?

It returns until the relay, its control wiring, or the pump is repaired.

Transmission controls Generic OBD-II High

What it means

P0945 means the control circuit for the transmission's hydraulic pump relay is open or malfunctioning. On transmissions that rely on an electric pump for line pressure, this can leave the gearbox without the pressure it needs to engage or shift. The engine still starts, but the transmission may not drive properly — treat it as a get-it-looked-at-now fault.

High

Can I keep driving? Limited — if the hydraulic pump can't run, the transmission may lose pressure and fail to engage or shift; avoid driving until it's diagnosed.

Real-world scan data

Seen in

scans in the past year

Found in

<0.1%

of scans

<0.1%

of scans that found faults

Appears alongside · share of P0945 scans

P1711in 66.7% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

Common symptoms

What you'll notice

Check-engine light on
Non-operational hydraulic pump
Loss of line pressure / failure to engage gears
Harsh shifting or transmission won't shift
Transmission may enter limp mode or not drive

Common causes

Most likely first

Faulty hydraulic pump relayLikely
Open or short in the relay control-circuit wiringCommon
Loose or corroded connectors / damaged harnessCommon
Faulty hydraulic pumpLess often
Faulty transmission control module (TCM) — least likelyLess often

How to diagnose & fix

Work through it in order

Confirm the code and locate the hydraulic pump relay.
Inspect the relay, connectors, and control wiring for opens or corrosion.
Test the relay and its control signal from the TCM.
Verify the hydraulic pump runs and builds pressure.
Repair wiring or replace the relay/pump as confirmed. Clear and re-test.

FAQ

Quick answers

Is it safe to drive with P0945?+

Treat this as a stop-and-diagnose fault. Without the hydraulic pump the transmission can lose the pressure it needs to engage or shift, which risks leaving you stranded or damaging the gearbox.

Can I just clear P0945?+

It returns until the relay, its control wiring, or the pump is repaired.

Read & clear P0945 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX