Powertrain, generic (extended)

P2C12 B Camshaft Profile Actuator Position Sensor A Circuit Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Camshaft B is the exhaust camshaft in J2012 terms, and P2C12 reports an open circuit in the feedback of its first profile actuator on bank 1. GM's 2.7 L turbo L3B (Silverado and Sierra 1500 from model year 2019) is the documented user: its tables call this element exhaust Hall sensor 1. With the driver energised, the ECM flags a break once the signal-to-ground impedance reaches 200 kilohms or more; four failures out of five samples at system voltage above 11 V give a Type A code, MIL on trip one (19OBDG03D, 25OBDG03B). P2C12 is in the main DTC list of PIT5677 and its successor 21-NA-149, which point to engine harness damage at the camshaft carrier cover. Exhaust lift changes are then suspended. Low and high: P2C14, P2C15.

Likely causes

Engine harness worn through where it crosses the camshaft carrier cover (GM PIT5677, 21-NA-149)
Connector on exhaust actuator 1 not latched or corroded
Open Hall element inside the exhaust actuator

Symptoms

  • Check engine light from the first trip
  • Exhaust cam profile no longer switched, fuel economy mode unavailable
  • With harness damage, several other engine codes at the same time

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–4 h

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

Parts involved

b camshaft profile actuator pos sensor a b1wiring harnessecm

Related codes

P2C13P2C14P2C15P2C16P2C05P002A

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