P0788Shift Timing Solenoid A High
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- Needs a drive cycle to confirm a fix
- How the car detects it
- 'Shift timing solenoid' means different parts: on GM's 4L60-E the 3-2 downshift solenoid that times the band apply on that downshift, on Aisin five-speeds (GM, Saab) the linear valve SLS that sets clutch pressure during the shift, and on the 2017–18 Genesis G80/G90 with shift-by-wire the on/off solenoids that engage drive (A) and reverse (B). P0788 means the circuit is shorted to positive or draws overcurrent. GM's 4L60-E checks the 3-2 downshift solenoid output for an invalid state at more than 43 of 50 counts; GM's Aisin-type five-speed flags SLS current above 1356 mA for 2 s and lights the MIL at once. Limp mode and shift jolts follow; the opposite is P0787.
- What you may notice
- Warning lamp
- Limp mode
- Shift jolts
- Likely causes
- LikelyShort to positive in the harness
- PossibleWinding short in the solenoid
- RareModule driver stage
- 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: €100 – €800
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.