Powertrain, generic · Auxiliary emission controls

P049E EGR B Control Position Exceeded Learning Limit

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. Circuit B is the second EGR path; on diesels with two circuits it is the low-pressure EGR, which takes exhaust after the particulate filter and feeds it in before the turbo compressor (GM diesels 2016–18, FCA's 2.2 and 3.0 diesels). P049E is the counterpart of P049D for valve B: the learned zero point of its position sensor lies outside the permitted window. GM lists it only in a fault group of its low-pressure EGR (whose position sensor is sensor C there, P044C/P044D), and in the 2016 calibration it is explicitly disabled; thresholds are not published. The description therefore follows GM's P049D strategy by analogy. Low-pressure EGR position control is then switched off.

Likely causes

Low-pressure EGR valve sooted, does not close fully
Position sensor of the low-pressure valve faulty or shifted
Valve replaced without teaching in
Harness or connector of the low-pressure valve

Symptoms

  • Check engine light on
  • EGR switched off, usually no noticeable change
  • Higher NOx

Repair estimate

DifficultyHardWorkshop job
Parts and labour€0–1,000
Time0.5–4 h

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

Parts involved

low pressure egr valveegr valve b position sensorengine control module

Related codes

P049DP045EP045FP044CP044DP049B

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