P0785: Shift Timing Solenoid A

'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). P0785 is the general circuit code for solenoid A. GM's 2006 tables use it for the 3-2 downshift solenoid circuit (more than 43 of 50 failed counts, after one trip); Saab's 2002 Aisin box for an open or short in the SLS circuit with warning lamp and limp mode; Hyundai's Genesis bulletins for the drive solenoid, replacing valve and electronic module and then the module if it returns. Limp mode, harsh 3-2 downshifts or – on the Genesis – no drive follow.

Symptoms

• Warning lamp
• Limp mode
• Harsh 3-2 downshift (GM) or rough shifts (Aisin)
• Genesis shift-by-wire: drive cannot be engaged

Most likely causes

• Solenoid coil open or shorted
• Connector or wire at the transmission (oil, corrosion)
• Electronic module or transmission module driver

What to check, in order

Start with the simplest. You can tick off each step.

1. Check the oil level and condition before anything else
2. Check the solenoid valve's connector
3. Compare commanded and actual angles in live data
4. Test the solenoid valve and its filter, if it has one
5. Check the engine timing if there is chain noise

Good to know

• Repair difficulty: medium
• It can trigger limp mode.
• It affects emissions.

What each character of P0785 means

• P: Powertrain: engine and transmission
• 0: Generic code: same on every make
• 7: Transmission
• 85: Specific fault in that system

Frequently asked questions

Can I keep driving with code P0785?

Drive little and gently. If you hear timing chain noise or the oil light comes on, shut off the engine.

What causes code P0785?

The most common causes are: solenoid coil open or shorted; connector or wire at the transmission (oil, corrosion); electronic module or transmission module driver.

Related codes

• P0786Shift Timing Solenoid A Range/Performance
• P0787Shift Timing Solenoid A Low
• P0788Shift Timing Solenoid A High
• P0789Shift Timing Solenoid A Intermittent
• P078AShift Timing Solenoid B
• P0750Shift Solenoid A

Sources

• gsi.ext.gm.com: 2006trans11
• saabwisonline.com: p0785
• static.nhtsa.gov: MC 10125169 9999
• static.nhtsa.gov: MC 10202185 0001

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.