Powertrain, generic · Auxiliary emission controls

P045C EGR B Control Circuit Low

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. P045C means the drive circuit of valve B is shorted to ground (for valve A, P0489, GM uses 0.5 Ω or less with the driver off, MIL after two trips). The driver is switched off for protection and the valve stays in its rest position. GM lists this code among those that switch off the low-pressure EGR position control, but publishes no thresholds for it; the description follows the comparable valve A checks and CARB, which requires output circuits to be monitored.

Likely causes

Control wire chafed against ground (engine, exhaust)
Actuator motor winding shorted
Water or corrosion in the connector
Driver in the engine module

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€80–700
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

P045DP045AP0489P044C

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