P240F
EGR Slow Response
The EGR system reacts to commanded changes more slowly than calibrated - typically a partly clogged EGR cooler, sticky valve, or worn actuator.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: medium
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Common causes
Ordered by how often each turns out to be the cause.
- EGR valve or cooler stickyCommon
Parts involved
- EGR Valve A
- EGR Cooler A
P240F is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.