Powertrain, generic (extended)

P2B53 A Camshaft Profile Actuator B Control Stuck On Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2B53 means actuator B of the bank 1 intake camshaft is caught in the engaged position. GM documents it for the L3B 2.7-litre four as pin stuck: after a shift the Hall feedback must climb back above the retracted level of 68; if extending (55) or extended (45) was seen but the pin never reports home before the engine cycle ends, the ECM logs a stuck-out pin. One failure in five samples is enough, Type A, MIL on the first trip. GM bulletins PIT5677 and 21-NA-149 also list P2B53 among codes a chafed engine harness on 2019–2022 Silverado and Sierra can trigger. A pin left in the groove can hold the sleeve or wear it, so profile switching is disabled. Opposite fault: P2B4F.

Likely causes

Actuator pin does not retract (sticking plunger, varnish, weak spring)
Engine harness chafed on the camshaft carrier (GM PIT5677 / 21-NA-149)
Hall feedback does not report the home position although the pin is back

Symptoms

  • MIL on in the first drive
  • Lift switching and cylinder deactivation locked out
  • With a damaged harness also other codes, rough running or blown fuses
  • Possible ticking from the valve cover if the pin rubs in the groove

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–800
Time0.5–4 h

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

Parts involved

a camshaft profile actuator b b1wiring harnessecm

Related codes

P2B4FP2B54P2B55P2B34P003D

References: gsi.ext.gm.com, gsi.ext.gm.com, static.nhtsa.gov, static.nhtsa.gov.