Powertrain, generic (extended)

P27CF Pressure Control Solenoid R Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P27CF tells that the control line of solenoid R is held low, as if shorted to ground. On the Corvette dual-clutch transmission GM (23OBDG07, still present in 24OBDG07) monitors synchronizer actuation valve 4 while energized; the driver chip compares the sense pin with a threshold of roughly 1.7 V and, after 150 ms below it, reports a ground fault rated Type A. Ford's TR9070 list gives P27CF to a shorted switch on SPV4. A ground short bypasses the driver, so the valve can apply rods 3 and 4 towards A when no shift is wanted; the controller then usually locks the affected gears. Chafed insulation, a crushed harness clip or a coil shorted to its housing are typical finds.

Likely causes

Chafed insulation grounding the control line
Harness crushed at a clip or bracket
Solenoid R coil shorted to its housing

Symptoms

  • MIL on
  • Unwanted rod movement, gears locked out
  • Limp mode

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€100–900
Time1–4 h

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

Parts involved

pressure control solenoid rwiring harness

Related codes

P27D0P27CDP27CEP27CBP27C7P27BF

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