What it means
Coolant pump F is commanded on but does not respond as expected. Pump motor stuck, relay weld, or driver fault.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Coolant pump F circulates coolant through a vehicle cooling circuit separate from or additional to other pumps, depending on the design. P2D27 sets when the control module commands pump F on but detects that this specific pump is stuck off or fails to respond as expected.
Common causes
Most likely first.
- Pump motor mechanically stuck
- Output driver fault
- Carbon or debris buildup preventing free movement
Symptoms
- Check-engine or hybrid-system warning
- Power limited warning
- Reduced performance under load
How to diagnose it
- Use a scan tool to review freeze-frame data and pump F command and status, confirming the fault occurred when pump F was requested to run.
- Check coolant level and inspect pump F, its hoses, and its wiring for leaks, impact damage, or a disconnected connector.
- Safely command pump F on if the scan tool supports it and check for operation, listening or feeling for a stalled motor.
- Inspect pump F's connector, fuse, relay, and harness for corrosion, overheated terminals, opens, or poor connections.
- Test pump F's motor and control circuit against the manufacturer's specification to identify a stuck pump, wiring issue, or output driver fault.
Common fixes
- Reconnect or repair loose or damaged wiring at pump F.
- Replace a failed fuse or relay after checking why it failed.
- Remove an obstruction only if the manufacturer's procedure permits pump service.
- Replace pump F if it is mechanically stuck or fails its electrical test.
- Repair the control module output circuit if testing confirms a driver fault.
Can I keep driving?
Limit driving and avoid heavy loads because a nonworking pump F can reduce cooling in the circuit it serves and trigger power limits. Stop safely if a temperature warning appears or the vehicle reports a hybrid-system fault.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.