P2728Pressure Control Solenoid E Control Circuit Range/Performance
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- P2728 marks the circuit of solenoid E as working but not plausible. GM uses it in two ways. On the Allison 1000 (16OBDG08, 17OBDG04) the TCM compares desired with actual current on PCS 1; a gap of at least 0.5 A in 10 of fewer than 20 samples sets a Type A fault with MIL. On the T76 six-speed table of 2016, where valve E serves the 1-2-3-4 clutch, an invalid voltage flag for 4.4 of 5 s sets it without MIL. Bulletin PI0893 explains the second case for 2013 vehicles with the 6T70/6T75: as a Type C history code next to P2719 and P0965 it can appear falsely with fluid between -0.5 and 0 °C in Park or Neutral and needs no parts. MIL behaviour therefore depends on the gearbox.
- What you may notice
- MIL on Allison-equipped trucks
- History code without symptoms on GM six-speeds
- Firm shifts if pressure control is degraded
- Likely causes
- LikelyCoil current deviating from command (resistance change, poor contact)
- PossibleFalse history code near 0 °C fluid temperature (GM 6T70/6T75)
- RareUnstable supply voltage to the TCM
- RareWorn solenoid E
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Usually a job for a workshop.Typical cost: €0 – €1,200
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.