Powertrain, generic (extended)

P2738 Pressure Control Solenoid F Control Circuit Low

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

P2738 reports a control line on solenoid F that reads too low, which in practice means a short to ground. In GM's 2025 table 25OBDG03A an impedance below 0.5 Ohm between the signal and controller ground, lasting 0.3 s inside a 0.5 s sampling period, is a Type A fault in one trip; the valve there controls a clutch on the nine- or ten-speed, line pressure on the eight-speed or the CVT binary pump. The eight-speed table of 2016 uses the same timing. The Corvette dual-clutch TCM tests the clutch cooling valve with its driver switched on and sets P2738 when the measured pin voltage remains below roughly 1.7 V for 150 ms. Ford's TR9070 labels the same condition shorted switch on the odd clutch cooling valve. A grounded line can energise the valve permanently.

Likely causes

Control wire chafed through to ground
Shorted turns in solenoid F
Fluid or metal debris bridging connector pins
Faulty TCM output stage

Symptoms

  • MIL on and fail-safe gear
  • Harsh engagements or clutch drag

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–1,500
Time0.5–5 h

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

Parts involved

pressure control solenoid fwiring harness

Related codes

P2734P2736P2737P2739P2729P2814

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