Coolant Mixing Valve Control Circuit
Generic electrical fault on the coolant mixing valve control. The valve blends hot and cold coolant streams to maintain stack temperature.
Affected components
- Coolant mixing valve
- Valve wiring
Common causes
- High likelihood: Valve actuator failed
- Low likelihood: Gateway module routing CAN messages incorrectly
- Low likelihood: CAN terminating resistor (120 Ω) drifted out of spec
Possible symptoms
- Multiple warning lights may illuminate
- Affected modules may go into limp mode or shut down
- Specific functions inoperative depending on module
- Diagnostic tools may show communication faults
Diagnostic notes
- The malfunction indicator lamp may illuminate
- A drive cycle may be required after repair
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.