P041A
EGR Temperature Sensor B Circuit
A general electrical fault on EGR temperature sensor B — open, shorted, or out of plausibility. The sensor monitors recirculated exhaust gas temperature for EGR cooler protection and dosing.
- 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.
- Sensor failedCommon
Parts involved
- EGR Temperature Sensor
P041A 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.