What it means
The engine coolant pump runs below the calibrated minimum speed for the commanded duty. Mechanical resistance high or supply voltage low.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
The engine coolant pump circulates coolant through the engine and radiator to control engine temperature. This code sets when pump speed falls below the module's expectation for its command, risking inadequate cooling, especially under load.
Common causes
Most likely first.
- Mechanical load increased (binding)
- Supply voltage low under load
Symptoms
- Check-engine light
- Engine temperature may rise
- Engine may overheat under load
How to diagnose it
- Record freeze-frame data and check live engine temperature, pump command, and reported pump speed to see whether the fault coincides with rising temperature.
- When the engine is fully cool, check coolant level and inspect for leaks, damaged hoses, or obstructions around the pump and cooling system.
- Inspect the pump's electrical connector, wiring, and grounds for corrosion, looseness, or heat damage.
- Measure pump supply voltage and ground performance while it is commanded on, comparing results with the manufacturer's specification.
- If the electrical supply is sound, check for mechanical pump binding and verify pump speed response against the manufacturer's specification.
Common fixes
- Repair coolant leaks and refill with the specified coolant when the engine is cool.
- Clean or repair loose, corroded, or damaged pump wiring and connections.
- Correct a weak power or ground supply to the engine coolant pump.
- Replace the engine coolant pump if it binds or remains underspeed with correct electrical supply.
Can I keep driving?
Do not continue driving if the temperature rises, an overheating warning appears, or coolant is leaking; stop safely and let the engine cool. Continuing under load with an underspeed pump can lead to severe engine damage.
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.