Powertrain, generic · Transmission

P08DC Shift Solenoid K Control Circuit High

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

The monitored control line of shift solenoid K sits closer to supply voltage than it should, for instance because it touches a powered wire or, depending on the driver design, because the coil is open. No manufacturer documents this code publicly. GM treats the solenoid A version, P0974, as open or power short and fails it after 1.2 of 1.5 seconds, but lights the MIL only after two trips. Ford's P0974 means a short to power only, because Ford reports opens separately. CARB requires this circuit check. P08DB is the low counterpart, P08DD the open-circuit code. A valve shorted to power may stay energised, giving a wrong gear or harsh engagements.

Likely causes

Control wire touching a powered conductor

Open coil on systems that read opens as high

TCM low-side driver no longer pulls the line down

Symptoms

Check engine or transmission warning light on
Wrong gear or harsh engagement
Possible limp mode

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–1,500

Time1–5 h

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

Parts involved

shift solenoid kwiring harness

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