What it means
The control module detects that the EGR system response is slower than expected. The code identifies a response problem, but does not by itself establish a clogged cooler or a failed actuator.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
The exhaust gas recirculation (EGR) system routes some exhaust back into the engine to reduce nitrogen oxide emissions. The control module monitors how quickly the EGR system responds to a command and sets P240F when that response is slower than expected. A slow response can result from a sticking valve or restricted passages, but the code alone does not identify the failed part.
Common causes
Most likely first.
- Sticking or restricted EGR valve or passages
- EGR actuator or control fault
- Wiring or connector fault
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
How to diagnose it
- Record freeze-frame data and compare commanded with actual EGR position or flow data, if available, to see how the response lags.
- Inspect EGR wiring and connectors for damage or poor contact that could delay actuator response.
- Check the EGR valve and accessible passages for sticking, deposits, or restriction using the manufacturer's inspection procedure.
- Test EGR actuator movement and feedback while commanding the valve with a scan tool, where supported.
- If valve movement is normal, check EGR flow and related control components against the manufacturer's specification.
Common fixes
- Repair a damaged EGR connector or wiring fault.
- Clean restricted EGR passages if the manufacturer's procedure permits it.
- Free or replace a sticking EGR valve.
- Repair or replace a faulty EGR actuator or control component.
Can I keep driving?
You may notice hesitation, power loss, rough idle, or pinging under load; avoid heavy acceleration and towing until it is diagnosed. Continued operation with poor EGR response can raise NOx emissions and may worsen drivability.
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.