Powertrain, generic (extended)

P2B33 A Camshaft Profile Actuator B Control Circuit/Open Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2B33 concerns the second profile actuator on the intake camshaft (camshaft A) of bank 1. Such actuators are solenoids that extend a pin into a groove on a sliding cam sleeve and so move lobes of a different lift under the valves. GM uses the code on the 2.7-litre turbo four L3B (Silverado and Sierra 1500 from 2019), whose sliding cam system has four intake and two exhaust actuators; GM calls this one actuator 2. The ECM energises the output and flags an open circuit when it sees 200 kΩ or more between signal and ground in 4 of 5 samples, with supply above 11 V; MIL on the first trip (Type A). With the sleeve unable to move, lift switching and cylinder deactivation stay locked out. Low and High are P2B34 and P2B35.

Likely causes

Connector at the actuator on the camshaft carrier loose, corroded or not latched after valve cover work
Solenoid winding of actuator B open
Control wire broken in the engine harness
Output stage in the engine control module faulty

Symptoms

  • MIL on after the first drive with the fault
  • No change of intake lift profile, less pull or higher fuel use depending on the stuck profile
  • Cylinder deactivation no longer engages

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time0.5–3 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

P2B34P2B35P2B36P2B39P001AP2B4F

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