Powertrain, generic (extended)

P23F1 Camshaft B Position Signal Output Circuit High (Bank 2)

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

P23F1 means the camshaft B output for bank 2 sits at a high level that the ECM did not command. Its driver switches the line to ground to form the pulses; if the line stays high while switched, current is coming in from elsewhere – typically a short to a supply wire in a shared harness bundle, sometimes water bridging terminals. The GM bank 1 camshaft A analogue P2616 judges this at 0.5 ohm or less to power, with at least 11 V at the powertrain relay, and classes it as Type C. There is no published manufacturer description of P23F1. Measure the line with the receiver unplugged: if the voltage disappears, the receiving module is the source. Counterparts are P23EE for bank 1 and P23F0 for a line stuck low.

Likely causes

Short to a supply wire within a shared harness bundle
Water bridging connector terminals
Receiving module feeding voltage back into the line
ECM driver no longer switching

Symptoms

  • Code present, no change in engine behaviour
  • Communication or plausibility faults in the receiving module

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€50–900
Time0.5–3 h

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

Parts involved

engine control modulecam position signal b b2 outputwiring harness

Related codes

P23EFP23F0P23EEP23EBP2616

References: gsi.ext.gm.com, law.cornell.edu.