Powertrain, generic · Transmission

P08C8 Pressure Control Solenoid M Control Circuit/Open

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

GM sets this code on the Corvette's Tremec dual clutch for an open circuit at synchronizer actuation valve 1, the valve for the odd-gear shaft. The open-load test runs with the low-side driver switched off: an intact coil pulls the sense pin to battery voltage, so if the driver chip can hold it between about 1.7 and 3 V (each ±0.5 V) with a very small current, the circuit is considered open. The fault must persist for 150 ms with battery voltage between 8.75 and 18 V and the engine not cranking; it is suspended while P0882 or P0883 indicates a supply problem. Type A, MIL at once. Without this valve the odd shaft cannot be shifted reliably, so a fallback mode is likely.

Likely causes

Connector at the control valve body loose or corroded

Broken wire in the internal harness

Solenoid coil open

Symptoms

Check engine light on immediately
Fallback mode with restricted gears

Repair estimate

DifficultyHardWorkshop job

Parts and labour€100–2,500

Time0.5–5 h

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

Parts involved

pressure control solenoid mwiring harness

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