What it means
Coolant pump A reports a supply voltage circuit condition. Coolant circulation through the affected loop cannot be commanded reliably.
At a glance
- Usually lights the check-engine light
- The engine or gearbox may go into limp mode
How it works
Coolant pump A needs electrical supply to circulate coolant through its assigned loop, and the control module monitors the pump's supply circuit. P2B9D sets when that supply circuit has a fault, such as an open or inadequate electrical feed, preventing reliable pump operation.
Common causes
Most likely first.
- Supply fuse blown
- Wiring or connector fault
Symptoms
- Check-engine light
- Coolant temperature warning or rising temperature gauge
- Reduced engine power
How to diagnose it
- Capture freeze-frame data and check pump A command and status with a scan tool, noting any coolant temperature warning or reduced-power event.
- Identify pump A and its fuse from the vehicle's service information, then inspect the fuse and supply wiring for visible damage.
- Check pump A's connector for corrosion, moisture, loose terminals, or a poor fit.
- With the correct wiring diagram, measure supply and ground at pump A under the conditions specified by the manufacturer.
- If the fuse is blown, check the pump and circuit for a short or excessive load before replacing it, and compare electrical tests with the manufacturer's specification.
Common fixes
- Repair a loose, corroded, or damaged pump A connector.
- Repair an open or damaged supply wire or ground connection.
- Replace a failed supply fuse after identifying and correcting the cause of failure.
- Replace pump A if its supply circuit is sound but it still fails to operate.
Can I keep driving?
Avoid driving if the coolant temperature rises or a temperature warning appears; stop safely and switch off the engine to prevent overheating damage. If temperature remains normal, have the supply fault diagnosed promptly because pump A may stop circulating coolant without warning.
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.