P0968 Code: Pressure Control Solenoid C Control Circuit Open

What the P0968 code means

Solenoids are electric valves that send oil pressure to the clutches and brakes inside the gearbox. Pressure control solenoid C regulates the pressure with which the clutches are applied. The transmission computer turns the solenoids on and monitors both their electrical circuit and the result (the input and output shaft speeds of the gearbox).

The P0968 code means the control circuit is open: the solenoid receives no current when it is commanded. It is an electrical fault, and the suspects are the wiring, the connector (very often the pass-through connector on the case, which leaks oil), the solenoid itself or the control module.

On any gearbox code, the first check is the oil: the right level using the manufacturer procedure (often with the engine running and at a set temperature), a red or pink color and no burnt smell. Low or degraded oil causes slipping, harsh shifts and solenoid or gear-ratio codes that disappear when it is corrected.

Measure the resistance of the component at its connector: infinite means it is open inside. If it reads correctly, follow the control wire back to the computer and look for a break, particularly in the stretches close to the exhaust and at in-line connectors.

See our P0700 guide to understand how gearbox codes are read and why you need a scan tool that can reach the transmission module.

P0968 code symptoms

• Check engine light or transmission light on.
• Shifts that are harsh, late or do not happen.
• Limp mode: the gearbox stays in a fixed gear (often 2nd, 3rd or 4th).
• Slipping or high rpm in certain gears.

Likely causes of the P0968 code

1. Gearbox connector with oil or corrosion. Very common on the pass-through connector on the case.
2. Internal or external wiring damaged by heat or rubbing.
3. Solenoid with an open or shorted coil. Its resistance is out of specification.
4. Transmission control module. Uncommon.

How to diagnose the P0968 code step by step

1. Check the oil level and condition using the manufacturer procedure.
2. Read all the codes from the gearbox module with a scan tool that can reach it.
3. Measure the solenoid resistance at the gearbox connector and compare it with the manual.
4. Check the insulation to ground. It should read infinite.
5. Command the solenoid with the scan tool and listen for the click.
6. Inspect the case connector and look for oil inside it or green pins.

How to fix the P0968 code

• Repair the connector or the wiring.
• Replace the solenoid (or the valve body if the solenoid is built into it).
• Clear the adaptations and do the relearn procedure.
• Clear the P0968 code and verify with a road test.

Technical reference data

• Shift solenoids (on/off): roughly 10 to 30 ohms.
• Pressure or linear solenoids (PWM control): roughly 3 to 8 ohms.
• Normal gearbox oil temperature: 70 to 95 °C (158 to 203 °F).
• Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

In many gearboxes the solenoids live in the valve body and you reach them by taking off the pan. In some, the solenoids are sold only together with the valve body or with a built-in control module. After replacing solenoids or the valve body, you usually have to clear the adaptations and run a relearn with a scan tool.

P0968 on Aisin

On many Aisin gearboxes the solenoids sit in the valve body and are reached by removing the pan.

P0968 on Jatco

On many Jatco gearboxes the solenoids sit in the valve body and are reached by removing the pan.

P0968 on GM

On the GM 6T gearbox the solenoids sit in the valve body and are reached by removing the pan.

P0968 on Ford

On the Ford 6R gearbox the solenoids sit in the valve body and are reached by removing the pan.

P0968 on Volkswagen

The Volkswagen DSG uses a mechatronic unit, and in many modern gearboxes the solenoids come with the control module built in.

Frequently asked questions about P0968