Powertrain, generic · Transmission

P0747 Pressure Control Solenoid A Stuck On

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

Pressure control solenoid A sets line or clutch pressure by current; most are 'normally high', so with no current – as in limp mode – maximum pressure applies. 'A' is usually the line pressure valve, on GM clutch-to-clutch transmissions (6T, 8L, 9T) the pressure valve of clutch 1. Ford does not use P0745–P0749 but P0960–P0963. P0747 means the valve is electrically fine but pressure stays applied. On GM's clutch-to-clutch units the off-going clutch 1 does not release – slip stays below 50 rpm (9-speed, 0.8 s on loaded downshifts), and Allison flags 25 rpm or less for 0.3–1 s, both after one trip. On line pressure valves it means permanently high pressure. Harsh, abrupt shifts, a tied-up transmission and a default gear follow. GM noted false settings on 2017 8-speeds: clear and retest first.

Likely causes

Pressure or clutch valve or spool sticking (dirt, debris)
Valve body worn
Software or false setting
Wrong or contaminated fluid
Clutch plates stuck or burnt

Symptoms

  • Harsh, abrupt shifts
  • Transmission ties up, engine speed drops on shifts
  • Limp mode or default gear
  • Check engine light

Repair estimate

DifficultyHardWorkshop job
Parts and labour€400–3,500
Time2–10 h

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

Parts involved

pressure control solenoid atransmission valve bodytransmission wiringtransmission control module

Related codes

P0746P0745P0748P0777P0752

References: gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com, gsi.ext.gm.com.