Powertrain, generic · Transmission

P093D Hydraulic Accumulator Solenoid Performance

Check engine lightOn
EmissionsRelevant
Drive cycleRequired
Limp modeNo

The accumulator solenoid circuit is electrically sound, but the accumulator system does not deliver the expected hydraulic result. No manufacturer documents P093D publicly. GM's comparable P171D on the 9-speed transmission watches turbine speed during an engine auto-start: if it exceeds a predicted value because holding clutches slip from too little stored pressure, it counts a failure, enabled between 0 and 110 °C transmission fluid temperature, Type B. Gears Magazine names a solenoid stuck open or closed, a leaking accumulator piston, clutch or valve body leakage and misplaced check balls as causes. P093A to P093C are the electrical faults. Stop-start is disabled and the restart may feel like a bang.

Likely causes

Accumulator solenoid stuck open (drains) or closed (no fill)
Accumulator piston or bore leaking
Leakage at clutch seals or a worn valve body
Missing or misplaced check ball after a rebuild

Symptoms

  • Engine stop-start disabled
  • Lurch or bang when the engine restarts
  • Firm shifts with adaptive learning frozen

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€250–2,500
Time2–10 h

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

Parts involved

hydraulic accumulator solenoidwiring harnesstcm

Related codes

P093AP093BP093CP0944

References: law.cornell.edu, gsi.ext.gm.com, gearsmagazine.com, patents.google.com.