Powertrain, generic (extended)

P27C9 Pressure Control Solenoid R Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Solenoid R is the fourth synchronizer pressure valve on the dual-clutch units that use it, and P27C9 says it failed to move anything. GM's 2023 and 2024 Corvette tables (23OBDG07/24OBDG07) call it shift solenoid 4; it acts on the same two rods as valve 3 but drives them back from B towards A. The integrity check commands that motion for each selector position and expects more than 100 µm of rod travel; anything less marks valve 4 hydraulically stuck off, Type A. Ford's TR9070 table lists P27C9 for SPV4. As the opposite direction is affected, the gearbox may be unable to move those rods back, so certain gears can be neither selected nor released.

Likely causes

Spool of solenoid R stuck closed
Supply passage or screen to valve R clogged by debris
Leaking actuator seal on the B-to-A side of rods 3/4

Symptoms

  • MIL on with transmission message
  • Gear stays engaged or cannot be selected
  • Reduced gear range

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€300–2,500
Time2–8 h

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

Parts involved

pressure control solenoid rvalve body

Related codes

P27CAP27CDP27C1P27D1P27B9P08C4

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