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DTC codes / P2Exx · Hybrid propulsion / P2E45

P2E45Hybrid/EV Electronics Coolant Pump B Enable Circuit

P2E45 indicates that the powertrain control module has detected a fault in the enable circuit for the electronics coolant pump B, which is used to circulate coolant through the hybrid or electric vehicle's power electronics. The computer monitors the enable circuit for expected voltage or current behavior and sets this code when the circuit does not respond as commanded, preventing the pump from running.

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

Symptoms you may notice

  • Illumination of the check engine light or service vehicle soon message
  • Often no symptoms besides the warning light, especially if the pump has not yet failed completely
  • Reduced hybrid system power or a forced limp mode in some vehicles
  • Overheating warnings for the hybrid or EV electronics, which may lead to shutdown
  • Inability to start or charge the vehicle in certain conditions if the pump is required for thermal management
  • Audible pump noise or lack of pump operation when the vehicle is powered on

Common causes, most likely first

  1. Open or shorted enable circuit wiring between the control module and the coolant pump
  2. Failed electronics coolant pump B, such as a seized motor or internal electrical fault
  3. Corroded or damaged electrical connector at the pump or control module
  4. Blown fuse or faulty relay supplying power to the enable circuit
  5. Faulty powertrain control module or hybrid control module driver for the enable circuit
  6. High resistance in the ground circuit for the pump

How to diagnose and fix it

  1. Verify the code with a scan tool and check for any related codes in the hybrid control module
  2. Inspect the coolant pump B connector and wiring for corrosion, damage, or loose pins
  3. Check the fuse and relay that supply power to the enable circuit and replace if faulty
  4. Measure voltage and resistance on the enable circuit at the pump connector while commanding the pump on with a scan tool
  5. Perform a resistance test on the pump motor and compare to specifications
  6. If the circuit tests good, substitute a known-good pump or use a bidirectional scan tool to command the pump and observe operation
  7. Repair or replace the faulty wiring, connector, pump, or control module as indicated by test results

Enable circuit faults often misdiagnosed as pump failure

  • A failed enable circuit can be caused by a simple blown fuse that also powers other components, so always check fuses before condemning the pump.
  • The pump may test good on a bench but still set this code if the control module driver is weak or the ground circuit has high resistance.
  • Some vehicles require the hybrid system to be powered down and the 12-volt battery disconnected before testing the enable circuit to avoid damage to the control module.
  • This code can be set intermittently by a loose connector that only loses contact during vibration or temperature changes, so wiggle tests are valuable.
  • Do not overlook the possibility of a software calibration issue in the control module that may require reprogramming after all hardware checks pass.

Can I keep driving with P2E45?

It is generally not safe to continue driving with this code because the electronics coolant pump may not operate, leading to overheating of hybrid components and possible system shutdown. Avoid driving until the fault is diagnosed and repaired, especially in warm ambient temperatures or during heavy load conditions.

Tools that help

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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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