Powertrain, generic · Transmission

P0785 Shift Timing Solenoid A

Check engine lightOn
EmissionsRelevant
Drive cycleNot required
Limp modePossible

'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.

Likely causes

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

Symptoms

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

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€150–900
Time1–4 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

shift timing solenoidtransmission wiringtransmission control module

Related codes

P0786P0787P0788P0789P078AP0750

References: gsi.ext.gm.com, saabwisonline.com, static.nhtsa.gov, static.nhtsa.gov.