P01EC: Engine Coolant Heater B Control Circuit/Open — what it means, the affected system and what to check before replacing parts.
Meaning, symptoms, causes and checks
The monitor reports a open control-circuit condition in the circuit for engine-coolant heater B. The code concerns the electrical control path; it does not prove that the heater must be replaced or that the coolant temperature is abnormal. Confirm applicability and follow the actual vehicle's service procedure.
Affected system: Powertrain
Symptoms
- Warning light may illuminate
- Related system function may be impaired
- Vehicle-specific symptoms vary
Possible causes
- Mechanical timing or operating issue, sensor or actuator fault, connector 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
- Record freeze-frame conditions; compare relevant live data and inspect mechanical operation, wiring and related fault codes before replacing parts.
- Confirm measured values against the vehicle service information
- Retest under the conditions that set the code
- Record freeze-frame conditions; compare relevant live data and inspect mechanical operation, wiring and related fault codes before replacing parts.
- Repair the verified cause and confirm the code does not return
Also written as: P01EC-00, P01EC00, PO1EC (some scan tools add the fault-type byte, e.g. -00).