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DTC codes / P0Cxx · Hybrid propulsion / P0CED

P0CEDHybrid/EV Electronics Coolant Pump A Enable Circuit

P0CED indicates that the hybrid or electric vehicle control module has detected a fault in the enable circuit for coolant pump 'A' that cools the power electronics, such as the inverter or onboard charger. The computer monitors the command signal and feedback circuit for this pump and sets the code when the circuit does not behave as expected, either because the enable signal is missing, shorted, or the pump's response is implausible.

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

Symptoms you may notice

  • Illumination of the hybrid system warning light or check engine light, often with no other noticeable symptoms.
  • Reduced hybrid system power or a forced limp mode that limits vehicle speed.
  • The power electronics coolant pump may not run at all, leading to overheating of the inverter or charger.
  • In some cases, the vehicle may fail to start or enter 'ready' mode because the hybrid system cannot safely operate.
  • A noticeable lack of cabin heat if the same coolant loop serves the heater core, though this is less common.
  • Audible warning chimes or messages on the driver information display indicating a hybrid system fault.

Common causes, most likely first

  1. A failed coolant pump 'A' motor or internal control module, which prevents the enable circuit from receiving proper feedback.
  2. Damaged or corroded wiring in the enable circuit, such as an open or short to ground or power.
  3. A blown fuse or relay that supplies power to the coolant pump enable circuit.
  4. Poor electrical connection at the pump harness connector, often due to water intrusion or terminal fretting.
  5. A fault in the hybrid control module itself, though this is less common and should be diagnosed last.
  6. Aftermarket accessories or improper previous repairs that tapped into the enable circuit and caused interference.
  7. Extreme temperatures or debris blocking the pump impeller, which can cause the pump to draw excessive current and set a circuit code.

How to diagnose and fix it

  1. Perform a visual inspection of the coolant pump, its connector, and the wiring harness for obvious damage, corrosion, or loose terminals.
  2. Check all fuses and relays related to the coolant pump enable circuit and replace any that are blown or faulty.
  3. Use a scan tool to command the coolant pump on and off while monitoring live data to confirm whether the pump responds and whether the enable signal is present.
  4. Measure voltage and resistance on the enable circuit at the pump connector and compare to manufacturer specifications to identify opens or shorts.
  5. Test the pump motor directly by applying power and ground to the pump terminals (if accessible) to verify it operates; if not, replace the pump.
  6. Inspect the hybrid control module connectors for tightness and corrosion, and check for any applicable software updates or technical service bulletins.
  7. If all circuits and the pump test good, follow the manufacturer's diagnostic flow chart to test the hybrid control module's output signal and replace it only if confirmed faulty.

What the enable circuit really monitors

  • The enable circuit is not just a power feed; it often includes a feedback line that tells the control module the pump is actually running, so a pump that spins but does not report back can still set this code.
  • A common misdiagnosis is replacing the coolant pump when the real fault is a corroded connector pin or a chafed wire behind the radiator, so always perform a voltage drop test under load.
  • Some vehicles use the same coolant pump for both power electronics and cabin heating, so a failure may present as a heater performance issue before any hybrid warning appears.
  • The code can be set by a momentary glitch, so check for stored freeze-frame data and review the repair history before condemning parts.
  • Aftermarket pumps or incorrect coolant mixtures can cause the pump to draw abnormal current and trigger the enable circuit code even though the pump runs.

Can I keep driving with P0CED?

Do not continue driving with this code set, because the power electronics may overheat and suffer permanent damage, leading to costly repairs. Have the vehicle towed to a qualified hybrid service facility if the warning light is on and the pump is not running.

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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