P0947
Hydraulic Pump Relay/Control Circuit Low
Transmission / hydraulic pump
Generic OBD-II
High
What it means
P0947 means the controller sees a low-voltage (shorted or open) condition on the hydraulic pump relay/control circuit. On transmissions that rely on an electric hydraulic pump, this circuit powers the pump that builds shifting pressure. The engine may still start, but losing pump operation can leave the transmission unable to shift or move, so this should be repaired promptly.
High
Can I keep driving? Risky — if the hydraulic pump loses power the transmission can lose the pressure it needs to shift or move, potentially stranding the vehicle. Fix promptly.
Common symptoms
What you'll notice
- Check-engine light on
- Transmission won't shift or engage gears properly
- Loss of hydraulic pressure / vehicle won't move
- Weak or inconsistent transmission operation
Common causes
Most likely first
- Faulty hydraulic pump relayLikely
- Short-to-ground or open in the relay control circuitCommon
- Damaged or corroded wiring/connectors in the circuitCommon
- Weak battery or low supply voltageLess often
- Failed pump control module (rare — check relay and wiring first)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and check battery/charging voltage.
- Inspect the hydraulic pump relay and its connector for corrosion, and the wiring for a short-to-ground or open.
- Test the relay and its control circuit; confirm the module commands it correctly.
- Replace the relay if it fails to actuate; repair wiring, and consider the control module only if the driver circuit is confirmed bad. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0947?+
Not really. Losing the hydraulic pump can leave the transmission without pressure to shift or move. Address it before driving further to avoid being stranded.
Can I just clear P0947?+
It returns until the relay, wiring, or supply voltage is fixed. Clearing does not restore hydraulic pump operation.
Related codes
Often seen with P0947
Read & clear P0947 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX