P2C68

Code

Generic P — Powertrain

Hybrid/EV Electronics Coolant Pump A Stuck/Stalled

Brand: Generic

Type: P — Powertrain

Views: UK: 20 EN: 43 RU: 21

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Page language: EN

Causes

Failed pump motor (electrical or mechanical seizure)
Obstructed or broken impeller or debris in pump housing
Air locked or severely low coolant level preventing flow
Open/short in pump supply, ground, or control wiring
Blown fuse or failed relay supplying the pump
Failed pump driver or control module output (PWM driver)

Symptoms

Malfunction Indicator Lamp (MIL) or warning light for hybrid/EV cooling
Diagnostic trouble code P2C68 stored
Reduced inverter/battery cooling and elevated temperatures
Power/torque derate or limited charging sessions
No audible pump noise when pump is commanded ON
Unusual noise (grind/squeal) from pump if impeller damaged

What to check

Scan for P2C68 and any related DTCs; view freeze frame and pending status
Visually inspect pump, connectors and wiring for damage, corrosion, or melting
Check coolant level and look for leaks or contamination
Listen for pump operation when commanded ON from a scan tool
Check fuse(s) and relay(s) for the pump circuit
Measure supply voltage at pump connector with engine/vehicle ON and pump commanded

Signal parameters

Pump supply voltage at connector when commanded ON — nominal: battery aux voltage (approx. 11–14 V for 12 V systems) or specified aux voltage; should be present when commanded
Pump motor current draw — typical: low amperage when free-running; stalled motor may show very high current or 0 A if open circuit (specs vary by vehicle)
Motor winding resistance (cold, power off) — expect low ohms (manufacturer spec); open/short indicates failure
Pump command signal (PWM duty cycle and frequency) from controller — duty changes with cooling demand; frequency often in the kHz range (varies by make)
Coolant temperature sensors (inverter/battery temps) — elevated if pump not circulating
CAN/diagnostic status messages for pump reported by inverter or thermal control module — check for mismatch between commanded and reported status

Diagnostic algorithm

Retrieve DTCs and freeze frame; note conditions when code set (ignition state, vehicle speed, temperatures).
Attempt to command Pump A ON using a capable scan tool while monitoring supply voltage and current at the pump connector. Observe whether pump runs, current changes, or fuses blow.
Inspect fuses and relays for continuity; replace suspect items and retest.
Visually inspect harness and connector for corrosion, pin damage, water ingress, or melted insulation. Wiggle test while commanding pump to detect intermittent faults.
With power removed, measure motor winding resistance across pump terminals. An open or shorted winding indicates pump replacement.
If pump draws high current when powered, allow brief tests only and isolate power quickly — remove pump and check for seized impeller or debris. Replace pump if mechanically seized or impeller damaged.
Check coolant level and bleed air from the circuit per manufacturer procedure; trapped air can mimic a stall by preventing flow.
If wiring and pump appear OK but no command/pulse present at connector, diagnose the pump driver/controller output (check PWM with oscilloscope or scan tool data). Replace control module only after confirming faulty output and ruling out wiring/connectors.
After repair, clear codes and perform system bleed and functional test under varying load/temperature conditions to verify proper operation and that code does not return.
Check for and apply any manufacturer software updates if intermittent faults or known service bulletins exist.

Likely causes

Pump motor mechanical seizure or stuck impeller
Open/short in pump power supply or ground circuit
Failed pump driver/module output
Low coolant level or air in the cooling circuit
Connector corrosion or wiring harness damage at pump

Fault status

⚠️ Status

Control detected Coolant Pump A stuck or stalled — pump commanded but not producing expected operation/flow. Inspect pump, electrical supply, wiring and cooling circuit.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0 - 3.0 hours