Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P05CF Cold Start B Camshaft Position Timing Performance Bank 2

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

During catalyst heating after a cold start the engine module commands a specific cam phaser position for more residual gas and exhaust heat; CARB requires this to be monitored under codes separate from the normal cam codes. These 'performance' codes are GM's current form (since about 2015/16; older GM engines and Ford use the direction codes P052A ff and P054A ff): fault when commanded and actual position differ by more than 4° or 6° once the target is stable. P05CF watches exhaust camshaft B on bank 2 of a V engine – the cold-start counterpart of P0024. GM's 3.6 L V6 sets it above 4° in 40 of 100 samples, type B, two trips. Its predecessor in GM's 2011 V6 (Saab 9-4X) was P054D, above 6° for 1 s.

Likely causes

Insufficient cold oil supply: wrong viscosity, low level, worn oil
Oil control valve bank 2 sticking or screen clogged
Phaser worn or lock pin not releasing; on electric phasers a damaged phaser motor
Timing chain stretched or skipped
Engine module software

Symptoms

  • Check engine light on (GM mostly after two trips)
  • Often no noticeable symptoms, possibly rough cold idle
  • Higher cold-start emissions

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–1,500
Time0.5–6 h

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

Parts involved

camshaft phaservct oil control valveengine oilengine control module

Related codes

P0024P05CEP05CDP054CP0019P0023

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, saabwisonline.com.