01 How To Use Engine Braking in Automatic Transmission • 02 How does an automatic transmission change gears smoothly: • 03 The Meaning of Major Dashboard Light: A Comprehensive Guide • 04 This Is Why Mixing Fuel Grades Or Pumping The Wrong Fuel De… • 05 Why Your Garage Has Customers But No Profit • 06 Is Your Car Burning Oil? Signs & Solutions for Oil on Spark… • 07 This Is Why Your Car’s Door Won’t Latch Properly • 08 What Causes Your RPM to Go Up and Down When You Brake? Find… • 09 Why Your Chassis Number is the Key to Finding the Perfect A… • 10 The Challenges of CVT Gearboxes: Troubleshooting and Repair •

DTC codes / P2Dxx · Hybrid propulsion / P2D07

P2D07Motor Electronics Coolant Pump B Underspeed

P2D07 indicates that the engine control module (ECM) has detected the coolant pump for motor electronics circuit B running at a speed lower than commanded or expected. The ECM monitors the pump's feedback signal and sets this code when the actual pump speed falls below the calibrated threshold for a given operating condition.

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

Symptoms you may notice

  • Illumination of the check engine light, often with no other noticeable symptoms
  • Reduced power or limp mode if the motor electronics coolant pump is critical to inverter or motor cooling
  • Overheating warning or elevated temperature readings for the electric drive components
  • Intermittent cooling fan operation or unusual fan noise as the system tries to compensate
  • Possible shutdown of the electric drive system in severe cases to protect components

Common causes, most likely first

  1. Low coolant level or air trapped in the motor electronics cooling circuit
  2. Faulty coolant pump B, such as worn brushes, seized bearing, or internal electrical failure
  3. Damaged or corroded wiring and connectors between the pump and the ECM
  4. Blown fuse or faulty relay supplying power to the coolant pump
  5. Restricted coolant flow due to a clogged radiator, hose, or heat exchanger in the motor electronics loop
  6. ECM software calibration issue or internal driver fault for the pump circuit

How to diagnose and fix it

  1. Check coolant level and inspect for leaks in the motor electronics cooling circuit, then bleed the system if air is suspected
  2. Perform a visual inspection of the pump, wiring, and connectors for damage, corrosion, or loose terminals
  3. Test the pump's power and ground circuits with a multimeter to confirm voltage supply and ground integrity
  4. Command the pump on with a scan tool and verify actual pump speed against commanded speed using live data
  5. Check for restricted coolant flow by inspecting hoses and the heat exchanger for blockage or kinks
  6. If electrical and hydraulic checks pass, replace the motor electronics coolant pump B
  7. After repair, clear the code and verify the pump reaches commanded speed during a road test

Coolant pump underspeed is not always the pump

  • A low coolant level or trapped air often causes the pump to cavitate and report underspeed, mimicking a failed pump
  • Corroded terminals at the pump connector can add resistance that reduces pump speed without setting a circuit code
  • The ECM may command the pump to a specific speed only under certain load or temperature conditions, so the fault may not appear during a simple idle test
  • Aftermarket pumps with incorrect impeller design or voltage requirements can trigger this code even when new
  • A restricted motor electronics radiator or heat exchanger can cause the pump to overwork and slow down, setting the code without any electrical fault

Can I keep driving with P2D07?

Do not continue driving if the check engine light is accompanied by a overheating warning or reduced power message, as the electric drive components can be damaged. If only the light is on and the vehicle drives normally, limit driving to a short distance to a repair facility and avoid heavy loads or high speeds.

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.

Running on fumes Free guides aren't free to make. Top up the tank. Any amount, one time. Fuel the Garage