Powertrain, generic · Auxiliary emission controls

P045B EGR B Control Circuit Range/Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modePossible

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. P045B means the drive circuit of valve B is electrically valid, but the feedback – current, voltage or position response – does not match the command. No manufacturer document available to us uses this code; the description follows the valve A counterpart P0404 and CARB, which requires output functions to be checked where feasible. Typical is a coked, stiff valve.

Likely causes

Valve B coked or stiff
Contact resistance in connector or wiring
Actuator motor worn internally
Engine module software or calibration

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€100–800
Time0.5–3 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

P045AP045EP045FP0404P049E

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