Powertrain, generic · Auxiliary emission controls

P041E EGR Temperature Sensor B Circuit Intermittent/Erratic

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

Exhaust gas recirculation (EGR) routes part of the exhaust back into the intake to lower combustion temperature and NOx. EGR temperature sensor B is the second temperature sensor in the EGR path; on GM diesels it sits before the cooler, on Ford diesels after it. P041E means its signal jumps. GM's diesels of 2016–18, the only documented users, set it when the measured resistance changes by more than 25 Ω between two samples 100 ms apart – faster than any real temperature change, so a loose contact or cracked sensor is the cause (40 of 50 samples, MIL after two trips). Dependent checks such as EGR cooler efficiency are then suspended.

Likely causes

Loose contact or corrosion at the sensor connector
Harness chafed or broken (heat at the EGR pipe)
Sensor cracked internally (thermal cycling)
Engine module or ground connection

Symptoms

  • Check engine light on, may come and go
  • Usually no noticeable symptom
  • Further EGR temperature or cooler checks suspended

Repair estimate

DifficultyEasyDIY possible
Parts and labour€30–250
Time0.5–1.5 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

egr temperature sensor bsensor wiringengine control module

Related codes

P041AP041BP041CP041DP040EP040F

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, law.cornell.edu.