Powertrain, generic · Transmission

P0786 Shift Timing Solenoid A Range/Performance

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). 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.

Likely causes

Valve worn or coil resistance drifting
Contact resistance at the connector
Unstable system voltage

Symptoms

  • Rough shifts
  • Warning lamp
  • Limp mode

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

P0785P0787P0788P078B

References: gsi.ext.gm.com, law.cornell.edu.