What it means
Charge air cooler coolant pump B reports a control circuit high condition. CAC coolant loop circulation is impaired.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Charge air cooler coolant pump B circulates coolant to carry heat away from compressed intake air. This circuit-high code sets when the ECM detects a control-circuit signal above its expected range, which may result from a short to battery voltage, an open pump motor, or poor connector contact.
Common causes
Most likely first.
- Control wire shorted to B+
- Open pump motor
- Connector pins corroded - high contact resistance
Symptoms
- Check-engine light
- Possible charge-air cooling or engine performance warning
How to diagnose it
- Record freeze-frame data and look for related pump B or charge-air temperature codes to establish the conditions when the circuit fault occurred.
- With the engine off, inspect pump B's connector for corrosion, loose fit, or damaged terminals.
- Trace the pump B control wire for harness damage or contact with a battery-voltage feed.
- Test the control circuit for an unintended connection to battery voltage and check pump B's motor for an open, using the wiring information.
- Compare pump and circuit results with the manufacturer's specification before identifying the failed component.
Common fixes
- Restore proper contact at pump B's connector.
- Repair a control wire shorted to battery voltage.
- Replace pump B if its motor is open or fails the manufacturer's specification.
- Repair a confirmed control circuit fault.
Can I keep driving?
Use light throttle and avoid towing or prolonged high-load driving because the charge air may not be cooled properly and engine performance can fall. Stop if a charge-air cooling warning appears or power drops significantly.
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.