P0947: Hydraulic Pump Relay Circuit Low — what it means, the affected system and what to check before replacing parts.
Meaning, symptoms, causes and checks
Hydraulic-pump relay circuit: The electrical input is below its permitted range. This signal-level finding does not by itself establish a mechanical failure. The relay-control circuit and the pump hydraulic output are different. A relay DTC does not prove a seized pump or authorize bypassing its control circuit.
Affected system: Transmission hydraulic sensing and pressure unit
Symptoms
- Warning light may illuminate
- Related system function may be impaired
- Vehicle-specific symptoms vary
Possible causes
- Low or unstable supply voltage, fuse or relay fault, poor ground, or wiring damage
- Related wiring, connector, power or ground fault
- Vehicle-specific mechanical or control issue
What to check
- Record stored and pending codes and freeze-frame data
- Measure battery and charging voltage under load and compare with scan data; test the named circuit, fuse, relay, grounds and connectors.
- Confirm measured values against the vehicle service information
- Retest under the conditions that set the code
- Measure battery and charging voltage under load and compare with scan data; test the named circuit, fuse, relay, grounds and connectors.
- Repair the verified cause and confirm the code does not return
Also written as: P0947-00, P094700, PO947 (some scan tools add the fault-type byte, e.g. -00).