OBD-II code · Powertrain (generic)
P040A EGR Temperature Sensor A Circuit
A general electrical fault on EGR temperature sensor A — open, shorted, or out of plausibility. The sensor monitors recirculated exhaust gas temperature for EGR cooler protection and dosing.
Is it safe to drive with P040A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelySensor failed
Symptoms
- Check engine light on
- Pinging or knocking under load
- Power loss and hesitation
- Possible rough idle
- Failed emissions inspection (NOx)
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- Parts involved
- Egr Temperature Sensor, Egr Cooler
Related codes
- P041AEGR Temperature Sensor B Circuit
- P04CEEGR Temperature Sensor C Circuit
- P04E5EGR Temperature Sensor D Circuit
- P0407EGR Sensor B Circuit Low
- P0408Exhaust Gas Recirculation Sensor "B" Circuit Low
- P0409Exhaust Gas Recirculation Sensor "B" Circuit High
- P040BEGR Temperature Sensor A Circuit Range/Performance
- P040CEGR Temperature Sensor A Circuit Low
- P040DEGR Temperature Sensor A Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.