P0CED

Code

Generic P — Powertrain

Hybrid/EV Electronics Coolant Pump A Enable Circuit

Brand: Generic

Type: P — Powertrain

Views: UK: 22 EN: 25 RU: 21

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Page language: EN

Causes

Open or short in the pump enable/control wiring
Corroded, loose or damaged connector at the pump or controller
Blown fuse or faulty relay supplying pump power or enable circuit
Failed coolant pump motor or internal driver
Faulty inverter/vehicle control module (pump driver) or software issue
Water intrusion or contamination of connector/harness

Symptoms

Hybrid/EV coolant pump A fails to run when commanded
HV battery / inverter / power electronics temperature warnings or faults
Reduced traction power, limp-home or derated system operation
Illuminated master warning light or hybrid system warning
Possible abnormal temperatures for power electronics under load
Diagnostic trouble codes stored for coolant pump or thermal management

What to check

Read and record all related DTCs and freeze-frame/fault data with a scan tool
Inspect pump connector and wiring for corrosion, damage, chafing or water ingress
Verify fuses and relays for the pump circuit and replace if blown or faulty
Monitor live data: pump enable command status and pump feedback (if available)
Check for correct supply voltage at pump power pins with key ON and when commanded
Measure continuity and resistance of enable/control circuit back to the controller

Signal parameters

Enable/control signal: typically a switched supply or PWM command — expect ~0 V (off) and ~5–12 V (on) depending on manufacturer; consult service manual for exact levels
PWM frequency (if used): typically in the low hundreds to a few kHz (e.g., 100–2000 Hz) — verify with scope
Pump supply voltage: near battery/12 V or vehicle low-voltage supply when key ON and when commanded
Typical running current: small coolant pumps often draw ~1–10 A depending on power rating; check actual spec for vehicle
Static motor resistance: low ohm range (consult service data); open or very high resistance indicates a broken winding

Diagnostic algorithm

Safety first: follow manufacturer hybrid/EV procedures. Place vehicle in Park, isolate high-voltage system if required and use appropriate PPE before working on high-voltage components or associated connectors.
Use a scan tool to read P0CED and any related codes. Note when the fault set (freeze frame) and any relevant temperatures or voltages.
With ignition ON (but with HV system handled per procedures), observe live data for the pump enable command while commanding the pump ON via the scan tool (bi-directional test).
Measure voltage at the pump connector power and enable terminals while commanding ON. Expected: enable command present and supply voltage at pump power. If command present but pump not running, suspect pump or pump ground.
If enable command is absent, trace enable/control circuit back to the controller. Check connector pins, continuity, and for shorts to ground or battery using a DVOM and wiggle testing.
Inspect and test all fuses, relays and wiring harness sections for corrosion, damage, or water intrusion. Repair or replace as required.
Measure pump current while commanded ON. No current or very low current with correct enable indicates an open motor or internal pump electronics failure; excessive current indicates seized or shorted motor.
If wiring and pump check good, test or substitute the controller/driver module if allowed by service manual. Check for related firmware/TCU/ECU updates.
After repairs, clear codes and perform verification run under load to confirm normal operation and that code does not return.
Document repairs and advise customer about any conditions observed (corrosion, water entry, damage) that could cause recurrence.

Likely causes

Open or intermittent enable wire connection between controller and pump
Corroded or damaged connector at pump harness
Failed pump motor or pump internal electronics
Blown fuse or defective relay in pump power/enable circuit
Controller/pump driver fault or software anomaly

Fault status

⚠️ Status

Enable/control circuit fault detected for Hybrid/EV Electronics Coolant Pump A — enable signal absent, intermittent, or out of expected range; pump may not run when commanded.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours