Powertrain, generic (extended)

P2CC4 Generator Voltage Sense Circuit B High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

P2CC4 indicates that generator sense circuit B reads above its upper limit. Either the line is shorted to a higher voltage, or the voltage at the measuring point really is excessive, for example because the regulator keeps the field fully energised; Remy warns that a full-field alternator can quickly push the system above 16 V. A meter separates the two cases: with the engine running, compare the sense voltage with the voltage directly at the battery posts. No manufacturer documents P2CC4 publicly. CARB does not require a MIL for charging inputs unless emissions or other monitors are affected, so the battery warning light is the more likely signal. Sustained overvoltage can damage lamps and electronics. Low signal: P2CC3; circuit A high: P063D.

Likely causes

Regulator of alternator B stuck in full field, real overvoltage
Sense wire B shorted to a higher-voltage line
Sense input of the engine control module faulty

Symptoms

  • Charging warning lamp on
  • Very high system voltage, bulbs failing early
  • Battery gassing or smelling

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€20–700
Time0.5–2.5 h

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

Parts involved

generator voltage sense circuitalternatorwiring harness

Related codes

P2CC1P2CC2P2CC3P063DP0563

References: autoprollc.com, serdia.deutz.com, law.cornell.edu.