Powertrain, generic (extended)

P27C7 Pressure Control Solenoid P Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P27C7 points to a control circuit of solenoid P that is too low, effectively a short to ground on the switched side. GM's 23OBDG07 Corvette dual-clutch table checks synchronizer actuation valve 3 with its low-side switch on and expects the sense resistor voltage to be pulled down only so far; a reading under about 1.7 V (±0.5 V) for 150 ms is reported by the driver chip as a ground short, Type A, provided the engine is not cranking and battery voltage lies between 8.75 and 18 V. With that line grounded, valve 3 may stay energized regardless of command. Ford lists the same failure as a shorted switch on SPV3 of the TR9070. Inspect harness routing near the case and the connector for moisture.

Likely causes

Control wire shorted to ground against the case
Moisture or oil bridging pins in the connector
Solenoid winding shorted to its housing

Symptoms

  • MIL on
  • Unwanted application of rods 3/4, gears blocked
  • 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 pwiring harness

Related codes

P27C8P27C5P27C6P27C3P27CFP27BF

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