Powertrain, generic (extended)

P27BA Pressure Control Solenoid N Stuck On

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P27BA is the opposite fault to P27B9: solenoid N keeps applying pressure when it should be released. GM's dual-clutch table 23OBDG07 (Corvette) describes the effect of a synchronizer valve 2 stuck on as a constant push on one shift rod. Because the selector routes that pressure differently once the selector moves to another position, one rod relaxes or another moves although no movement was commanded; the TCM watches the rod position sensors for this, Type A, and 24OBDG07 keeps the check. Ford's TR9070 list pairs the same code with SPV2 hydraulically stuck on. Possible consequences are a gear dragging in, gear clash or a forced protective mode, because two gears on one shaft must never engage together.

Likely causes

Valve spool stuck open by contamination
Worn solenoid armature not returning to rest
Fluid contaminated with clutch or synchronizer wear particles

Symptoms

  • MIL and transmission warning
  • Gear clash or grinding on shifts
  • Limp mode with restricted gears

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 nvalve body

Related codes

P27B9P27BBP27BCP27C0P08C5P27C2

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