Powertrain, generic · Transmission

P08C3 Pressure Control Solenoid M

Check engine lightOn

EmissionsRelevant

Drive cycleNot required

Limp modePossible

Base code for the thirteenth pressure control solenoid; the letter is assigned by the manufacturer. GM uses letter M in the Tremec eight-speed dual clutch of the Corvette (RPO M1L/M1M): its 2023–2025 TCM tables name the part synchronizer actuation valve 1, which serves the odd-gear shaft, while valves 2 to 5 report under P27B9 onwards. GM does not set this base code but the specific ones: P08C4 and P08C5 for hydraulic sticking, P08C8, P08CA and P08CB for the circuit. No other manufacturer documents P08C3 publicly. If it appears, the module has seen a non-specific fault of this valve; the driver typically notices the warning light and rough or missing gear changes on that shaft.

Likely causes

Valve sticking from debris in the valve body

Fault in the solenoid wiring or connector

Worn or failed solenoid

Symptoms

Check engine light on
Rough or missing shifts in odd gears
Possible fallback mode

Repair estimate

DifficultyShop_onlyWorkshop job

Parts and labour€200–4,000

Time1–6 h

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

Parts involved

pressure control solenoid mvalve body

References: gsi.ext.gm.com, static.nhtsa.gov, law.cornell.edu.