Powertrain, generic (extended)

P27B9 Pressure Control Solenoid N Performance/Stuck Off

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P27B9 says pressure control solenoid N does not build hydraulic force when commanded. On dual-clutch gearboxes this letter belongs to the second synchronizer pressure valve: Ford's 2024 summary lists it for SPV2 of the TR9070, and GM's 2023 Corvette table 23OBDG07 calls it shift solenoid 2 hydraulically stuck off. GM runs a synchronizer integrity routine after a shift-related fault or when the gear remembered at shutdown disagrees with the sensors at start-up; small test movements of the shift rods that stay at or below 100 micrometres with valve 2 actuated set the code, Type A, and 24OBDG07 keeps it. The driver may find gears on that rod unavailable.

Likely causes

Valve spool sticking closed from debris or varnish
Low or contaminated transmission fluid reducing supply pressure
Leak in the synchronizer actuator circuit
Mechanically binding shift rod or fork

Symptoms

  • MIL on
  • Certain gears cannot be selected; gear skipping
  • Substitute mode with reduced gear set

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

P27BAP27BBP27BCP27BDP08C4P27C1

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