Powertrain, generic (extended)

P2B39 B Camshaft Profile Actuator B Control Circuit/Open Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Camshaft B is the exhaust camshaft, and actuator B is the second shifting solenoid on it. On GM's 2.7-litre L3B the exhaust side has only two such actuators, so this is the last of them; GM's tables call it exhaust camshaft profile actuator 2. P2B39 flags an open control circuit: with the output commanded on, the ECM reads an impedance of at least 200 kΩ to ground. It needs 4 failures in 5 samples, a supply above 11 V and key in crank or run, and it turns the MIL on in the first trip. A loose connector on the camshaft carrier, a broken wire or an open coil are the usual causes. The exhaust sleeve then stays put, so the engine cannot change profile on that side. The intake counterpart is P2B33.

Likely causes

Exhaust actuator connector loose or corroded on the camshaft carrier
Broken wire in the engine harness
Open solenoid coil in exhaust actuator B

Symptoms

  • MIL on in the first drive
  • Exhaust lift profile no longer switches, cylinder deactivation unavailable

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

b camshaft profile actuator b b1wiring harnessecm

Related codes

P2B3AP2B3BP2B3CP2B33P002AP2B51

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