Open circuit or short to voltage in the pump control wiring or connector (corrosion, chafing, pushed-out pins); Faulty electronics coolant pump with an internal electronic fault; Low 12 V supply or poor earth to the pump or its control unit causing a wrong circuit reading; Blown fuse or faulty relay in the pump supply, where the system is fitted with one; Fault in the hybrid or power electronics control unit driver circuit; Outdated control unit software where the manufacturer has issued a known fix for this code.

P0CEC

Hybrid/EV Electronics Coolant Pump A Control Circuit High.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
C: AreaHybrid propulsion
EC: FaultThe specific fault in that area

What it means

P0CEC is a generic powertrain code meaning the control unit has detected a high voltage or high signal condition in the control circuit for hybrid or EV electronics coolant pump A. This pump circulates coolant through the power electronics, such as the inverter or converter. The control unit commands the pump and monitors the circuit, and it set the code because the circuit state did not match the command, typically a short to voltage or a fault in the driver.

Symptoms

Warning lamp on, such as the hybrid system, check engine or power electronics temperature warning
Reduced power or limited performance (limp mode)
Hybrid or EV system derating or reduced charging and regeneration
Coolant pump not running or noisy running
Power electronics overheating message after prolonged driving
Hybrid system may refuse to enter ready mode

Possible causes

Open circuit or short to voltage in the pump control wiring or connector (corrosion, chafing, pushed-out pins)likely
Faulty electronics coolant pump with an internal electronic faultlikely
Low 12 V supply or poor earth to the pump or its control unit causing a wrong circuit readingpossible
Blown fuse or faulty relay in the pump supply, where the system is fitted with onepossible
Fault in the hybrid or power electronics control unit driver circuitrare
Outdated control unit software where the manufacturer has issued a known fix for this coderare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting any related coolant pump, temperature or low voltage codes
Check the 12 V battery condition and charging voltage, as low voltage can cause false circuit faults
Inspect the coolant level in the power electronics cooling circuit and look for leaks or air locks (follow the manufacturer's procedure and observe high voltage safety precautions)
Visually inspect the pump wiring and connector for damage, corrosion, water ingress and bent or loose pins
Check the relevant fuse and relay, where fitted, and the supply and earth at the pump connector with a multimeter
Use a scan tool to command the pump on and off, and listen and feel for pump operation
Test the control wire for a short to voltage or an open circuit with the connector disconnected, following the wiring diagram for that model
Check for available software updates or technical bulletins for the specific model and engine

How to fix

Repair or replace damaged wiring and clean or replace corroded connectors
Replace the electronics coolant pump if it fails operation or electrical tests
Replace a blown fuse or faulty relay after finding the reason it failed
Repair the 12 V supply or earth connections, or replace a weak 12 V battery
Bleed and top up the power electronics cooling circuit using the manufacturer's procedure
Replace or update the control unit only after the wiring and pump are proven good, using the manufacturer's approved calibration where an update is a known fix

Can I keep driving?

Medium severity

Short, gentle driving may be possible, but without proper cooling the power electronics can overheat and the vehicle may go into limp mode or shut down. Have it checked soon and stop driving if a temperature warning appears.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.