Powertrain, generic · Ignition system or misfire

P03F8 B Camshaft Position Actuator Position Sensor C Circuit Low Bank 1

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

On some engines the exhaust cam phaser (camshaft position actuator B) has its own position sensors, which tell the engine module where the phaser actually is; sensor C is the third of them, bank 1 the side with cylinder 1. This is a different family from the sliding-cam position sensors (P2C05 ff). P03F8 means the signal stays below its lower limit – signal wire shorted to ground, 5 V supply open, or the sensor shorted internally. No manufacturer document available to us uses this code (GM, Ford and FCA tables checked); the intake counterpart P03E5 ff is equally unused. The phaser is then usually held in its base position.

Likely causes

Signal wire shorted to ground or 5 V supply open
Sensor faulty internally
Connector corroded
Engine module

Symptoms

  • Check engine light on
  • Exhaust cam phasing held in its base position, loss of power
  • Possibly rough idle or poorer emissions

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–700
Time0.5–3 h

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

Parts involved

cam phaser position sensor ccam phaser exhaust bank1sensor wiringengine control module

Related codes

P03F6P03F7P03F9P03E7P2B49P0014

References: law.cornell.edu, patents.google.com.