'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.
Medium severity. Can I keep driving?Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
Symptoms
- Warning lamp
- Limp mode (GM: fixed third gear)
- Harsh shifts from maximum pressure
Most likely causes
- Wire open or shorted to ground
- Solenoid coil open
- Module driver stage
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It can trigger limp mode.
- It affects emissions.
What each character of P0787 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 7: Transmission
- 87: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0787?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P0787?
The most common causes are: wire open or shorted to ground; solenoid coil open; module driver stage.
Related codes
- P0785Shift Timing Solenoid A
- P0788Shift Timing Solenoid A High
- P0786Shift Timing Solenoid A Range/Performance
- P078CShift Timing Solenoid B Low
Sources
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.