P2CB5: Charge Air Cooler Coolant Pump B Control Module Overtemperature

What it means

Charge air cooler coolant pump B reports a control module overtemperature 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

Pump B's control module manages the pump that circulates coolant through the charge air cooler loop. This code sets when that module reports excessive internal temperature, which can interrupt pump operation and reduce cooling of compressed intake air.

Common causes

Most likely first.

1. Ambient temperature too high
2. Module cooling path blocked

Symptoms

• Check-engine light
• Reduced engine power
• Possible charge-air temperature warning

How to diagnose it

1. Read freeze-frame data and live module temperature and pump B status to see whether overheating follows a particular operating condition.
2. With the vehicle safely switched off, inspect the control module area for dirt, debris, damaged covers or blocked airflow around its cooling path.
3. Check the module connector and wiring for corrosion, loose terminals or heat damage that could impair operation.
4. Inspect for nearby heat sources or unusually high ambient heat that could raise module temperature.
5. If the cooling path and wiring are clear, test module operation and its temperature reading according to the manufacturer's specification.

Common fixes

• Remove debris blocking airflow around the module cooling path.
• Repair or secure damaged module wiring and connectors.
• Correct a nearby heat shield or airflow obstruction if it is directing excess heat toward the module.
• Replace the control module if it continues to report overtemperature with a clear cooling path and sound wiring.

Can I keep driving?

Avoid high load and towing because an overheated pump control module may interrupt CAC coolant circulation and reduce power. Stop if a charge-air temperature warning appears or power drops sharply.