P0787Shift Timing Solenoid A Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- 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). P0787 means current or voltage in the circuit is too low – an open circuit or short to ground. GM's 4L60-E checks the 3-2 downshift solenoid output (more than 43 of 50 counts) after one trip and then sets maximum line pressure, holds third gear and disables the converter clutch; GM's Aisin-type five-speed flags SLS current below 92 mA for 12.5 s. The opposite is P0788.
- What you may notice
- Warning lamp
- Limp mode (GM: fixed third gear)
- Harsh shifts from maximum pressure
- Likely causes
- LikelyWire open or shorted to ground
- LikelySolenoid coil open
- 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.