Powertrain, generic (extended)

P2B3A B Camshaft Profile Actuator B Control Circuit Low Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2B3A points to a short to ground in the control line of exhaust-side actuator B on bank 1, i.e. the second pin solenoid that slides the lobe sleeve along camshaft B. GM documents it for the L3B four-cylinder in its 2019 and 2025 OBD tables: driver on, a resistance to ground not above 0.5 Ω, 4 of 5 samples, supply over 11 V, Type A with immediate MIL. Unlike its neighbours, P2B3A is missing from the code list of bulletin PIT5677, which prints P2B39 twice instead, yet the harness chafing over the camshaft carrier described there produces exactly this kind of ground fault. With the exhaust sleeve stuck, the engine loses part of its lift switching. Open and short to power are P2B39 and P2B3B.

Likely causes

Engine harness rubbed through where it crosses the camshaft carrier
Shorted turns in exhaust actuator B
Oil wicking into the actuator connector

Symptoms

  • Check engine light on immediately
  • Exhaust profile and cylinder deactivation no longer switch
  • With harness damage often further codes and rough running

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–600
Time1–4 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

P2B39P2B3BP2B3DP2B34P002B

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