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DTC codes / P2Cxx · Hybrid propulsion / P2CB5

P2CB5Charge Air Cooler Coolant Pump B Control Module Overtemperature

P2CB5 indicates that the control module for the charge air cooler coolant pump B has detected an internal overtemperature condition, meaning the electronics that drive the pump are running hotter than their design limit. The computer is not reporting a pump performance fault directly; it is flagging that the pump's control module has exceeded a safe temperature threshold, which can trigger protective shutdown of the pump.

SystemPowertrain
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaHybrid propulsion

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms.
  • Reduced engine power or limp mode if the pump shuts down and charge air temperatures rise.
  • Inconsistent or weak air conditioning performance if the same coolant circuit also serves the A/C condenser.
  • A warning message on the dashboard indicating a cooling system or powertrain fault.
  • In rare cases, elevated intake air temperatures leading to pinging or poor acceleration.
  • No driver-perceptible change in vehicle behavior besides the warning light.

Common causes, most likely first

  1. A failing charge air cooler coolant pump control module due to internal component degradation or thermal fatigue.
  2. Restricted coolant flow through the charge air cooler circuit, such as a blocked passage or a collapsed hose.
  3. Low coolant level or air trapped in the charge air cooler coolant circuit, reducing heat transfer and causing the pump to overheat.
  4. A faulty coolant temperature sensor or wiring that misreports temperature to the control module, triggering a false overtemperature code.
  5. Electrical issues such as high resistance in the pump power or ground circuits, causing the module to work harder and overheat.
  6. A seized or dragging coolant pump motor that overloads the control module and generates excess heat.
  7. Software or calibration issues in the control module that cause overly sensitive overtemperature detection.

How to diagnose and fix it

  1. Verify coolant level and condition in the charge air cooler circuit, and pressure-test the system for leaks or air pockets.
  2. Inspect the pump and control module connectors for corrosion, loose pins, or damaged wiring, and check ground connections.
  3. Use a scan tool to monitor charge air cooler coolant temperature sensor readings and compare them with actual temperatures to rule out sensor errors.
  4. Command the coolant pump on with a bidirectional scan tool and listen for operation; check for unusual noise or lack of flow.
  5. Measure voltage and resistance on the pump control module power and ground circuits to ensure they are within specification.
  6. If electrical and coolant flow checks pass, replace the charge air cooler coolant pump control module or the pump assembly as required by the manufacturer's procedure.
  7. After repair, clear the code and perform a road test to confirm the pump operates correctly and the code does not return.

Overheating module, not always the pump

  • A common misdiagnosis is to replace the coolant pump itself when the actual fault is the control module overheating due to a poor ground connection or high resistance in the power circuit.
  • Air trapped in the charge air cooler circuit after a coolant service is a frequent cause of this code because the pump runs dry and overheats, so proper bleeding is critical.
  • The code can set intermittently if the pump is commanded to run at high duty cycles during heavy load or hot ambient conditions, and may not reappear during normal driving.
  • Some vehicles use the charge air cooler coolant pump to also cool the EGR cooler or transmission, so a fault here can affect multiple systems and set related codes.
  • A failing pump motor that draws excessive current can overheat the control module without completely seizing, so current draw testing is more reliable than a simple listen test.

Can I keep driving with P2CB5?

You can usually continue driving to a repair shop, but avoid heavy throttle and sustained high-load conditions that demand maximum charge air cooling. If the engine enters limp mode or you notice overheating symptoms, stop and have the vehicle towed to prevent damage.

Tools that help

Tools we recommend are in the Auto Veteran shop on Amazon. As an Amazon Associate we earn from qualifying purchases.

Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.

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