P094E

Code

Generic P — Powertrain

Hydraulic Pump Supply Voltage Circuit/Open

Brand: Generic

Type: P — Powertrain

Views: UK: 18 EN: 43 RU: 25

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Page language: EN

Causes

Blown fuse or tripped circuit breaker in the pump supply circuit
Faulty pump supply relay or control module output
Open or damaged wiring harness (broken wire, chafing, corrosion)
Poor or corroded connector pins at the pump or module
Failed hydraulic pump motor (open winding)
Poor ground connection or high-resistance ground

Symptoms

Hydraulic pump does not run when commanded
Warning lamp or message related to hydraulic system or service required
Loss or reduction of hydraulic-assisted functions (transmission pressure, brake assist, active ride height, etc.)
Related fault codes stored in control module
Possible unusual noises or no noise from pump when it should operate

What to check

Retrieve freeze frame and related codes with a scan tool; note when the code set (key ON/engine running, during command, etc.).
Visual inspection of pump connector, wiring harness, fuses, relays, and mounting for damage, corrosion, or water intrusion.
Check fuse(s) and relay(s) for the hydraulic pump supply; replace or swap with known-good if available.
Backprobe pump supply connector and measure voltage with key ON and while commanding pump ON with a scan tool.
Measure voltage drop between battery positive and pump supply terminal while pump is commanded.
Check ground continuity and resistance from pump ground to chassis/battery negative.

Signal parameters

Expected pump supply voltage: approximately battery voltage (typically 11–15 V) with key ON and while pump is commanded.
Acceptable voltage drop: small — system voltage should not fall more than ~1–2 V under pump load; significant drop indicates wiring, fuse, or battery issue.
Pump winding resistance: low ohms for motor (varies by design); an open (infinite) reading indicates a failed motor winding or disconnected circuit.
No PWM frequency expected on a simple supply circuit; if controlled by module it may be switched or pulsed — use manufacturer data if available.

Diagnostic algorithm

Connect a scan tool. Read and record P094E and any additional codes or freeze-frame data. Note when the code was stored (key ON vs. running).
Perform a careful visual inspection of the pump, connector, and wire harness for damage, corrosion, or water entry. Repair obvious issues.
Check and, if necessary, replace the fuse(s) and inspect the pump supply relay. If relay is suspect, try a known-good relay.
With ignition ON (engine off) backprobe the pump supply terminal. Verify battery voltage at the connector. If no voltage, trace back to fuse/relay and module.
Command the pump ON using the scan tool (if supported) and measure supply voltage while commanded. Observe voltage drop under load. Low voltage or loss of supply when commanded indicates wiring, fuse, relay, or battery problem.
Disconnect power and measure pump motor winding resistance at the connector. An infinite/open reading indicates a failed pump motor; very low or shorted readings indicate electrical fault.
Check ground continuity from the pump ground terminal to battery negative. Repair high-resistance or corroded ground connections.
If wiring and connectors check good and pump motor shows proper resistance, verify the control module output for proper switching and inspect module grounds and power supply. Replace or repair as required per manufacturer procedures.
After repairs, clear codes and perform functional test and road test (or system exercise) to confirm the fault does not return.

Likely causes

Blown fuse or faulty relay preventing supply voltage to the pump
Open wire or disconnected connector between the pump and module
Corroded/loose connector at the pump causing intermittent open
Failed pump motor windings presenting as an open circuit

Fault status

⚠️ Status

Hydraulic pump supply voltage circuit open or out of specification. Pump may not operate; inspect supply fuse/relay, wiring, connector, ground, and pump motor.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-2.5 hours