Powertrain, generic · Auxiliary emission controls

P045F EGR B Control Stuck Closed

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 B is a second EGR valve next to valve A – on diesels with two EGR circuits the low-pressure valve, which takes exhaust after the particulate filter and feeds it in before the turbo compressor. GM's diesels of 2016–18 and FCA's 2.2-litre diesel in the Jeep Wrangler use it. P045F means valve B does not open: its actual position stays below the target despite the open command. GM lists the code among those that switch off low-pressure EGR control; Ford's comparable valve A check (P042F) compares the position with a calculated lower limit. Too little EGR raises NOx while driving stays normal. Icing or condensate can block a low-pressure valve – FCA runs its cleaning routine only above 0 °C.

Likely causes

Low-pressure valve coked or stuck
Actuator motor or gear faulty
Icing or condensate in the low-pressure circuit
Position sensor reports a wrong position

Symptoms

  • Check engine light on
  • Low-pressure EGR switched off, possibly higher NOx
  • Usually no change in driving

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–1,200
Time0.5–4 h

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

Parts involved

egr valve blow pressure egr valveegr wiringengine control module

Related codes

P045EP042FP0401P044CP049E

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