What it means
Voltage on the third coolant pump control line is above the expected window. Typical causes are a short to battery or an open motor winding.
At a glance
- Usually lights the check-engine light
How it works
Coolant Pump C circulates coolant through a separate cooling loop, and the control module monitors the electrical condition of its control line. This code sets when the line reads above its expected range, which can result from a short to battery voltage or an open pump winding.
Common causes
Most likely first.
- Control wire shorted to B+
- Open motor winding
- Connector pins corroded - high contact resistance
Symptoms
- Engine or powertrain warning light may come on
- Temperature warning may appear if the affected cooling loop overheats
- Cooling performance may be reduced in the affected system
How to diagnose it
- Record freeze-frame data and check live data for Pump C command and fault status to identify when the high reading occurs.
- With the system cool, inspect Pump C's connector and control-line wiring for damaged insulation, exposed conductors, corrosion, or loose pins.
- Check the control wire for an unintended connection to battery voltage using the manufacturer's procedure.
- Test the control wire for continuity and check for an open circuit, following the manufacturer's specification.
- If the wiring and connector are sound, test the Pump C motor winding against the manufacturer's specification.
Common fixes
- Clean corroded connector pins and secure the Pump C connection.
- Repair control-line wiring shorted to battery voltage.
- Repair an open connection in the control circuit.
- Replace Pump C if its motor winding is open.
Can I keep driving?
Avoid driving if a temperature warning appears or the affected loop is not cooling, since overheating can damage the engine or other components. If temperatures remain normal, limit driving and monitor for a warning.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.