What it means
The control module monitors Reductant Pump A and detects that it remains on when it should be off. The code describes the pump’s stuck-on condition; it does not identify the cause.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Reductant Pump A supplies DEF/AdBlue to the SCR dosing system, and the control module monitors whether the pump is operating when requested. P201F sets when Pump A remains on after it should have switched off; the code identifies the stuck-on behavior but does not establish whether a relay, wiring, driver, or pump is responsible.
Common causes
Most likely first.
- Pump relay contacts welded
- Pump driver line shorted to B+
- Carbon or debris buildup preventing free movement
Symptoms
- Check engine light or NOx warning on
- AdBlue/DEF level or quality warning
- Possible no-start countdown after ignore period
- Failed emissions inspection (NOx)
How to diagnose it
- Save freeze-frame data and check SCR, DEF pressure, and pump command/status data to confirm when Pump A is being kept on.
- Inspect Pump A wiring, connector, and relay area for damage, moisture, or evidence of overheated or welded contacts.
- With the manufacturer's scan-tool procedure, compare the pump command with its actual electrical state after the system requests it off.
- Test the Pump A relay contacts and check whether its driver wire is shorted to battery positive, following the wiring diagram.
- If the relay and wiring switch correctly, test the pump for mechanical sticking or internal failure to the manufacturer's procedure.
Common fixes
- Repair a damaged Pump A connector or wiring short that holds the pump on.
- Replace Pump A's relay if its contacts are welded or fail to open.
- Repair a driver wire shorted to battery positive after locating the damaged section.
- Replace Reductant Pump A if it continues running with correct circuit control and fails the manufacturer's test.
Can I keep driving?
Avoid extended driving and respond promptly to any DEF/NOx warning, since SCR faults can lead to reduced power or a no-start countdown. A pump that continues running may also damage the reductant system, so have it diagnosed before the vehicle becomes inoperable.
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.