What it means
Coolant pump D 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 D circulates coolant through the portion of the cooling system assigned to it. The control module monitors whether pump D responds when commanded on; P2C49 sets when that response is missing or inadequate, such as when the pump is stuck or its output driver does not operate it.
Common causes
Most likely first.
- Pump motor mechanically stuck
- Output driver fault
- Carbon or debris buildup preventing free movement
Symptoms
- Check-engine light or coolant-system warning
- Engine or component temperatures running high
- Cooling fan running more often than usual
How to diagnose it
- Use freeze-frame and live data to check the temperature trend and whether pump D was commanded on when the fault occurred.
- With the system cool, inspect pump D and its connector and harness for damage, leaks, loose terminals, or debris.
- Command pump D on with a scan-tool output test if supported, and check for pump operation and expected coolant movement.
- Test the pump D power, ground, relay, and control-driver circuit using the vehicle wiring information and manufacturer's specification.
- If the electrical supply and command are present but pump D does not run, check for mechanical sticking or obstruction by the specified method.
Common fixes
- Reconnect or repair a loose or damaged pump D connector or wiring.
- Remove debris or buildup that is restricting pump D, if the pump is serviceable.
- Repair a failed relay or pump D control-driver circuit.
- Replace coolant pump D if it remains stuck or fails the commanded operation test.
Can I keep driving?
Stop driving if temperatures rise or a coolant-system warning indicates overheating, since loss of pump D circulation can damage the engine or cooled component. If temperatures are normal, keep any necessary trip short and watch them closely.
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.