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DTC codes / P2Dxx · Hybrid propulsion / P2D0A

P2D0AMotor Electronics Coolant Pump C Stuck/Stalled

P2D0A indicates that the engine control module (ECM) has detected a stuck or stalled condition in the electric coolant pump circuit designated as 'C', which is typically an auxiliary pump used for motor electronics cooling. The ECM monitors the pump's command signal and feedback, and when the actual pump response does not match the expected current or speed, it sets this code.

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 cooling performance for the motor electronics, potentially leading to power derating in electric or hybrid vehicles.
  • Overheating warnings or messages on the dashboard if the pump is completely stalled.
  • Audible noise or lack of noise from the coolant pump area when the ignition is turned on.
  • In some cases, the vehicle may enter a limp mode to protect the electronics.

Common causes, most likely first

  1. Failed electric coolant pump (mechanical seizure or electrical failure).
  2. Blown fuse or faulty relay supplying power to the pump.
  3. Damaged or corroded wiring and connectors in the pump circuit.
  4. Blockage or restriction in the coolant hoses leading to the pump.
  5. Low coolant level or air trapped in the cooling system causing the pump to run dry.
  6. Faulty engine control module (ECM) or pump control module, though rare.

How to diagnose and fix it

  1. Check the coolant level and inspect for leaks or air pockets in the system.
  2. Verify the pump fuse and relay, and test for power and ground at the pump connector.
  3. Perform a visual inspection of the wiring harness and connectors for damage or corrosion.
  4. Use a scan tool to command the pump on and off and observe the feedback data.
  5. Measure the resistance of the pump motor and compare to specifications.
  6. If electrical checks pass, remove the pump and inspect for mechanical binding or blockage.
  7. Replace the coolant pump if it fails electrical or mechanical testing, then clear the code and verify repair.

Diagnosing Pump C Stuck or Stalled

  • A stuck or stalled pump can be caused by debris in the cooling system, so flushing the system may be necessary after replacement.
  • Some vehicles use multiple coolant pumps, and pump 'C' often refers to a specific auxiliary pump for electronics cooling, not the main engine pump.
  • The ECM may set this code if the pump draws excessive current due to a failing motor, even if the pump still turns.
  • Intermittent faults can occur due to poor electrical connections that test fine when probed but fail under load or vibration.
  • Always check for technical service bulletins (TSBs) for the specific vehicle, as some models have known issues with pump connectors or software.

Can I keep driving with P2D0A?

If the check engine light is on but the vehicle drives normally and no overheating warnings appear, you can drive to a repair shop, but avoid heavy loads or long trips. If overheating warnings occur or the vehicle enters limp mode, stop driving and seek immediate assistance to prevent damage to the motor electronics.

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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