P23C5 — Engine coolant bypass valve C position-sensor circuit — high electrical level

P23C5 concerns engine coolant bypass valve C position-sensor circuit. The monitor reports an electrical level above its expected range. The monitor concerns valve-position feedback. A high electrical value does not establish that engine coolant temperature is high.

Affected system: Engine/coolant thermal control

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: P23C5-00, P23C500 (some scan tools add the fault-type byte, e.g. -00).