Powertrain, generic · Transmission

P078E Shift Timing Solenoid B Intermittent

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). Only Hyundai/Genesis is documented using solenoid B, and only with the base code P078A. No manufacturer document available to us uses this code; the description follows solenoid A (P0789: an intermittent circuit fault). A loose contact is the likely cause; the warning lamp comes and goes.

Likely causes

Loose contact

Coil with thermal dropouts

Symptoms

Occasional warning lamp
Shift jolts at times

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€80–700

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

P078A P078C P078D P0789

References: law.cornell.edu, static.nhtsa.gov.