Contaminated, degraded or low transmission fluid causing the solenoid valve to stick; Pressure control solenoid 'M' mechanically stuck or failed internally; Blocked or clogged transmission filter or valve body passages with debris or clutch material; Wiring or connector fault (short to voltage, chafed loom, corroded pins) in the solenoid circuit; Valve body wear or a sticking spool valve affecting pressure control; Fault in the transmission control module or an outdated software calibration known for this fault on some models.

P08C5

Pressure Control Solenoid M Stuck On.

Generic
Powertrain
Generic code
High severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
8: AreaTransmission
C5: FaultThe specific fault in that area

What it means

P08C5 means the transmission control module has detected that pressure control solenoid 'M' is stuck on, so it is delivering hydraulic pressure when it has not been commanded to, or the pressure does not drop when commanded off. The module sets the code when measured behaviour (such as clutch slip, gear ratio, pressure sensor feedback or solenoid current) does not match the commanded state. Which circuit or clutch solenoid 'M' refers to depends on the vehicle and gearbox, so check the manufacturer's information for the exact model.

Symptoms

Gearbox warning light or malfunction indicator lamp on
Harsh, delayed or flared gear changes
Gearbox stuck in one gear (limp mode) or restricted gear selection
Engine flare or slip between gears
Gearbox overheating or a burning smell from the fluid
Poor acceleration or a shudder at certain speeds

Possible causes

Contaminated, degraded or low transmission fluid causing the solenoid valve to sticklikely
Pressure control solenoid 'M' mechanically stuck or failed internallylikely
Blocked or clogged transmission filter or valve body passages with debris or clutch materialpossible
Wiring or connector fault (short to voltage, chafed loom, corroded pins) in the solenoid circuitpossible
Valve body wear or a sticking spool valve affecting pressure controlpossible
Fault in the transmission control module or an outdated software calibration known for this fault on some modelsrare

How to diagnose

Read all stored and pending codes and the freeze frame data, noting gear, temperature, speed and load when the fault set.
Check for related codes such as other solenoid, pressure, ratio or slip faults, and look for manufacturer service bulletins for the model and gearbox.
Check the transmission fluid level and condition (colour, smell, metal or friction material) following the manufacturer's procedure for that gearbox.
Inspect the gearbox wiring loom and connector for damage, fluid ingress, corrosion and chafing.
Measure the solenoid resistance and check the supply, earth and control signal against the manufacturer's specification.
Use a scan tool's live data to compare commanded and actual pressure or solenoid current, and run any available solenoid actuation test.
Check the fluid pan and filter for debris, which indicates internal wear.
If the electrical side is sound, inspect the valve body and solenoid for sticking, following the model-specific procedure.

How to fix

Correct the fluid level and replace degraded fluid and the filter using the specified type and procedure.
Replace the faulty pressure control solenoid and clean or inspect the valve body.
Repair or replace damaged wiring, terminals or connectors in the solenoid circuit.
Repair or replace the valve body, or overhaul the gearbox if wear or debris damage is found.
Update or reflash the transmission control module software only if the manufacturer lists an outdated calibration as a known cause, or replace a confirmed faulty module.

Can I keep driving?

High severity

Limit driving: a stuck-on pressure solenoid can cause harsh engagement, overheating and internal gearbox damage. Avoid driving other than a short, gentle trip to a workshop, and stop if the gearbox slips, overheats or goes into limp mode.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.