Powertrain, generic · Transmission

P08DB Shift Solenoid K Control Circuit Low

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

The TCM's output stage reports a voltage on the shift solenoid K control circuit below what the commanded state requires, the classic sign of a control wire rubbing through to ground or a coil with an internal short. No manufacturer documents this K code publicly. For solenoid A, GM's 6-speed tables set P0973 when a ground short is flagged for 1.2 out of 1.5 seconds, with at least 9 V supply and the engine running, and light the MIL after one trip; Ford lists P0973 as short to ground. CARB mandates the check. P08DC is the opposite fault and P08DD the open circuit. Many TCMs then disable the valve, so expect a limp-home gear.

Likely causes

Control wire rubbed through to ground

Internally shorted solenoid coil

TCM output stage fault

Symptoms

Check engine or transmission warning light on
Transmission stays in a limp-home gear
Reduced acceleration due to missing gears

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.