'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). P0786 means the circuit is intact but the solenoid does not reach its target current. GM's 2006 Aisin-type five-speed flags a deviation of more than 80 mA for 2.75 s at a steady commanded current above 835 mA, with 11–16 V and fluid above 20 °C, and lights the MIL at once. Rough shifts and limp mode follow; low and high circuit faults are P0787/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
- Rough shifts
- Warning lamp
- Limp mode
Most likely causes
- Valve worn or coil resistance drifting
- Contact resistance at the connector
- Unstable system voltage
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 P0786 means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 7: Transmission
- 86: Specific fault in that system
Frequently asked questions
Can I keep driving with code P0786?
Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.
What causes code P0786?
The most common causes are: valve worn or coil resistance drifting; contact resistance at the connector; unstable system voltage.
Related codes
- P0785Shift Timing Solenoid A
- P0787Shift Timing Solenoid A Low
- P0788Shift Timing Solenoid A High
- P078BShift Timing Solenoid B Range/Performance
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.