P23F1

Code

Generic P — Powertrain

Camshaft B Position Signal Output Circuit High Bank 2

Brand: Generic

Type: P — Powertrain

Views: UK: 25 EN: 30 RU: 24

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Page language: EN

Causes

Faulty camshaft position sensor B (bank 2)
Short to battery or to the 5V/reference supply on the sensor signal wire
Open or shorted wiring/connector (water intrusion, corrosion, damaged insulation)
Poor sensor ground or reference supply
Incorrect sensor installation or mechanical timing/reluctor wheel damage
Defective PCM/ECM input circuit

Symptoms

MIL/Check Engine Light illuminated
Hard starting or no-start condition
Rough idle, misfires or stalling
Reduced engine performance or limp-home mode
Poor fuel economy or irregular idle speed

What to check

Retrieve freeze frame and live data; confirm P23F1 active and note engine conditions when set
Visual inspection of camshaft sensor B (bank 2) connector, wiring harness and reluctor wheel
Back-probe the sensor connector with key on/engine off and with engine cranking/running
Measure reference voltage, signal voltage and ground at the sensor with a digital multimeter and oscilloscope if available
Wiggle test wiring while monitoring signal for intermittent change
Check resistance/continuity between sensor signal and PCM input and between sensor ground and chassis ground

Signal parameters

Typical Hall-effect camshaft sensor: reference supply ~5V (±0.5V), signal toggles ~0–5V; a steady signal >4.5V is considered 'high'.
Typical variable-reluctance (VR) type: AC amplitude varies with engine speed; no DC 'high' should be present—DC >1V indicates wiring/short to supply.
Expected signal behavior: a pulsed/square or alternating waveform synchronized to camshaft rotation; frequency increases with RPM.
PCM input idle thresholds: low

Diagnostic algorithm

Confirm code and conditions: Read codes and freeze-frame data. Clear the code, then attempt to reproduce while monitoring live camshaft B signal for bank 2.
Visual inspection: Inspect connector for bent pins, corrosion, melted insulation, oil/water contamination and secure mounting of sensor and reluctor.
Measure supply and ground: With key ON engine OFF, back-probe reference (usually 5V) and ground at the sensor connector. Repair if reference or ground missing/out of range.
Check signal at rest and cranking: With meter/oscilloscope measure the signal pin. If signal is a steady high near reference/battery voltage, suspect short to supply or failed sensor.
Isolate wiring: Disconnect sensor. Measure voltage on the signal circuit at the harness side. If the harness shows the high voltage with sensor disconnected, repair wiring/short to power. If harness is low and sensor shows high when connected, replace sensor.
Continuity and short checks: Check continuity from signal pin to PCM input and for shorts to battery positive or reference circuits. Repair any short/open found.
Wiggle and load test: With connector harness connected, wiggle wiring and retest to find intermittent faults. Apply non-destructive voltage/load tests if needed.
Replace sensor if wiring and PCM appear good: After replacement, clear codes and perform a road test to confirm sensor output returns to normal and code does not recur.
PCM check: If all wiring and sensor tests are good and fault persists, test/replace or reflash PCM per manufacturer procedures.