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DTC codes / P0Axx · Hybrid propulsion / P0A07

P0A07Motor Electronics Coolant Pump Control Circuit High

P0A07 indicates that the motor electronics coolant pump control circuit is reporting a high voltage condition, meaning the pump driver circuit is seeing more voltage than expected, often due to an open circuit or a short to power. The powertrain control module (PCM) monitors this circuit and sets the code when the voltage exceeds the normal operating range for a calibrated time.

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

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message
  • Often no symptoms besides the warning light
  • Reduced engine performance or limp mode due to overheating protection
  • Overheating warning light or temperature gauge reading high
  • Cooling fan running constantly or at high speed
  • Possible no-start or shutdown after extended driving if the pump fails to run

Common causes, most likely first

  1. Open circuit in the coolant pump control wire (broken wire, disconnected connector)
  2. Short to voltage on the control circuit (chafed wire contacting a power source)
  3. Faulty coolant pump motor or internal electronics
  4. Corroded or damaged electrical connector at the pump or PCM
  5. Failed PCM driver for the coolant pump circuit
  6. Blown fuse or relay supplying power to the pump control circuit
  7. Poor ground connection for the pump or PCM

How to diagnose and fix it

  1. Verify the code with a scan tool and check for related codes in other modules
  2. Inspect the coolant pump connector and wiring for damage, corrosion, or loose pins
  3. Measure voltage on the control circuit at the pump connector with the key on and engine off
  4. Check the pump ground circuit for excessive resistance using a voltage drop test
  5. Test the coolant pump motor by applying power and ground directly to confirm operation
  6. Inspect the PCM connector and wiring for signs of short to voltage or open circuits
  7. If all circuits test good, replace the coolant pump and clear the code to verify the repair

Before you replace the coolant pump

  • A high voltage code on a pump control circuit often results from an open circuit rather than a failed pump, so always check wiring continuity before condemning the pump.
  • The motor electronics coolant pump is frequently used on hybrid and electric vehicles to cool the inverter and motor, and a failure can lead to reduced power or shutdown without overheating the engine.
  • A short to voltage on the control wire can be caused by wire chafing against a 12-volt source, which may not blow a fuse but will set this code.
  • Some vehicles use a pulse-width modulated (PWM) signal to control the pump, and a high voltage code can be set if the signal wire is shorted to battery voltage.
  • After repairs, the code may require a drive cycle or a specific relearn procedure to clear, and simply clearing the code may not be enough if the underlying issue persists.

Can I keep driving with P0A07?

It is generally safe to drive short distances to a repair shop, but avoid long trips or heavy loads because a failed coolant pump can lead to overheating and potential engine damage. If the temperature gauge rises or a warning light appears, stop driving and seek immediate assistance.

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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