01 The Fleet Manager Who Runs 200 Vans Explains How To Cut Mai… • 02 What Happens If You Don't Change the Oil in Your Car? • 03 When Reconnecting The Battery, Which Terminal is Connected … • 04 That Rotten Egg Smell From Your Exhaust Isn't Normal: Here'… • 05 Common Car Starting Issues and How to Troubleshoot Them • 06 Manual Transmission Stalling: Solved! • 07 This Is Why It’s Almost Impossible To Sink A Modern Cruise … • 08 C0110 - Pump Motor Circuit Malfunction • 09 Alternator Versus Battery Which One Actually Keeps Your Car… • 10 How to Fix an Engine That Cuts Out and Restarts While Drivi… •

DTC codes / U06xx · Network communication / U062F

U062FLost Communication With Coolant Pump C

U062F is a generic network communication code indicating that a control module on the vehicle's Controller Area Network (CAN) bus has lost contact with the coolant pump designated as 'C'. The module that sets this code expects regular status messages from that pump over the communication bus, and when those messages stop arriving within the required time window, the module stores U062F and typically illuminates the warning light.

SystemNetwork
Code typeGeneric (all makes)
SeverityMedium
Fix difficultyIntermediate
AreaNetwork communication

Symptoms you may notice

  • Illumination of the check engine light or a dedicated service warning lamp on the dashboard.
  • Often no symptoms besides the warning light, especially if the pump is still running but its communication circuit has failed.
  • Overheating or elevated coolant temperature if the pump has actually stopped running.
  • Reduced engine power or a limp-home mode triggered by the module that lost communication.
  • A cooling fan that runs continuously or not at all because the module can no longer command the pump.
  • Intermittent warning light operation if the communication loss is caused by a loose connection or chafed wire.

Common causes, most likely first

  1. A failed coolant pump 'C' assembly, including its internal electronics or communication interface.
  2. Damaged, corroded, or disconnected electrical connector at the coolant pump.
  3. Open or shorted communication wire (CAN high or CAN low) between the pump and the module that monitors it.
  4. Blown fuse or poor ground connection supplying power to the coolant pump circuit.
  5. A fault in the control module that sets the code, such as a failed CAN transceiver or software issue.
  6. Low system voltage or a weak battery causing intermittent communication dropouts across the network.
  7. Aftermarket accessories or poor previous repairs that disturb the CAN bus wiring near the pump.

How to diagnose and fix it

  1. Verify battery voltage and charging system output, then clear the code and test-drive to confirm whether U062F returns.
  2. Inspect the coolant pump connector and harness for corrosion, loose pins, chafing, or signs of coolant contamination.
  3. Check the fuse and ground circuit for the coolant pump using a multimeter and a wiring diagram for the specific vehicle.
  4. Measure resistance and voltage on the CAN communication wires at the pump connector to rule out an open or shorted bus segment.
  5. If wiring and power are good, substitute a known-good coolant pump or perform an actuator test with a scan tool to confirm pump operation.
  6. Check for other communication codes on the same bus; multiple U-codes often point to a shared wiring or module fault rather than the pump itself.
  7. After repairs, clear all codes and verify communication with the coolant pump using live data before returning the vehicle.

What the coolant pump code hides

  • A pump that spins freely and moves coolant can still set U062F if its internal communication chip has failed, so a visual coolant flow test alone does not clear the pump.
  • Technicians often replace the coolant pump only to find the real fault is a chafed CAN wire behind the radiator shroud or near a sharp bracket.
  • Multiple U-codes involving different modules on the same bus usually indicate a network wiring or voltage problem rather than several failed components.
  • Some vehicles use the coolant pump as part of a separate LIN or PWM control circuit, and a fault there can mimic a CAN communication loss even though the code description mentions communication.
  • A weak battery or a failing alternator can cause intermittent U062F because modules drop off the bus during cranking or low-voltage events.

Can I keep driving with U062F?

If the engine temperature gauge remains normal and the warning light is steady, you can drive cautiously to a repair shop, but avoid heavy loads and long trips. If the temperature gauge climbs or a red overheating warning appears, stop driving immediately and have the vehicle towed to prevent engine damage.

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