What it means
The Coolant Pump A control circuit is detected as open. The code alone does not establish that coolant circulation is absent or that engine or aftertreatment temperatures are affected.
At a glance
- Usually lights the check-engine light
How it works
Coolant Pump A is an electrically controlled pump, and its control circuit carries the command or power needed for it to operate. This code identifies an open circuit in the Pump A control path; by itself, it does not prove that coolant flow has stopped or that a temperature problem has occurred.
Common causes
Most likely first.
- Open pump motor winding
- Broken control wire to the pump
Symptoms
- Check-engine light may illuminate
- Engine or aftertreatment temperature warning may appear
How to diagnose it
- Check freeze-frame data and scan-tool pump command or status to establish whether Pump A was expected to operate when the fault set.
- Inspect Pump A's connector and the visible control wiring for a disconnected plug, broken wire, pushed-back pin, or corrosion.
- Check the relevant fuse and relay, if fitted, using the vehicle's wiring information.
- Test continuity through the Pump A control circuit and pump winding, comparing results with the manufacturer's specification.
- If the wiring and pump winding are intact, check the control-module output and circuit operation under the manufacturer's test procedure.
Common fixes
- Reconnect and secure a loose Pump A connector.
- Repair a broken wire or pushed-back terminal in the Pump A control circuit.
- Replace a failed fuse or relay after checking for the cause of failure.
- Replace Pump A if its winding is confirmed open.
Can I keep driving?
Watch the temperature gauge and warnings closely; if the engine or aftertreatment temperature rises, pull over safely and switch off the engine. Avoid continued driving if Pump A is needed for cooling, because overheating can cause serious 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.