Damaged, chafed or broken wiring between the transmission control module and the solenoid; Corroded, loose or contaminated connector or pins at the transmission or internal harness plug; Pressure control solenoid M open-circuit internally (failed coil); Fluid contamination or wear debris affecting the solenoid and valve body; Fault in the transmission control module driver circuit; Low or degraded transmission fluid leading to solenoid overheating or failure.

P08C8

Pressure Control Solenoid M Control Circuit/Open.

Generic
Powertrain
Generic code
Medium severity

How this code is built

P: SystemPowertrain
0: Defined bySAE, the same on every car
8: AreaTransmission
C8: FaultThe specific fault in that area

What it means

P08C8 is a generic powertrain code meaning the transmission control module has detected an open circuit in the control circuit of Pressure Control Solenoid 'M'. The module drives the solenoid to regulate hydraulic pressure and saw no current flow or a voltage that showed the circuit was broken. Which clutch, gear or function solenoid 'M' controls depends on the transmission, so the manufacturer's data is needed to identify it.

Symptoms

Gearbox warning light or malfunction indicator lamp on
Transmission stuck in one gear (limp mode)
Harsh, delayed or flared gear changes
No engagement of certain gears or a loss of drive
Torque converter lock-up not working, leading to higher fuel use
Reduced power or restricted gear selection

Possible causes

Damaged, chafed or broken wiring between the transmission control module and the solenoidlikely
Corroded, loose or contaminated connector or pins at the transmission or internal harness pluglikely
Pressure control solenoid M open-circuit internally (failed coil)likely
Fluid contamination or wear debris affecting the solenoid and valve bodypossible
Fault in the transmission control module driver circuitrare
Low or degraded transmission fluid leading to solenoid overheating or failurepossible

How to diagnose

Read all stored and pending codes and review freeze frame data for gear, temperature and speed when the fault set
Check transmission fluid level and condition (where a dipstick or check procedure exists) and look for burnt smell or debris
Visually inspect the harness and connector at the transmission for chafing, oil ingress, corrosion or bent pins
Look up the wiring diagram to identify solenoid M's pins and the control module terminals for this model
With the connector disconnected, measure the solenoid resistance and compare it with the specification for that transmission
Check the wiring continuity from the control module to the solenoid and test for short to earth or supply
Command the solenoid with a scan tool's active test, if supported, and watch for a response
Check for software updates or technical bulletins applicable to the vehicle

How to fix

Repair or replace damaged wiring and renew any faulty terminals
Clean or replace corroded or oil-contaminated connectors, or the internal transmission harness where oil has wicked up it
Replace the faulty pressure control solenoid M, or the valve body or solenoid pack if it is supplied as a unit
Change the transmission fluid and filter to the correct specification if contamination is found
Replace or repair the transmission control module only after the wiring and solenoid have been proven good
Apply a manufacturer calibration update only if an outdated calibration is a known cause for that model

Can I keep driving?

Medium severity

The car may go into limp mode and further driving could damage the transmission through poor clutch pressure control. Drive only if needed and gently, and have it diagnosed soon.

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