P0936 Code: Hydraulic Pressure Sensor Circuit Intermittent

What the P0936 code means

Automated manual transmissions (Opel Easytronic, Fiat Dualogic, Toyota MMT, BMW SMG, Ford Durashift, Volkswagen ASG) and many dual-clutch gearboxes use electric or hydraulic actuators to release the clutch, pick the gear plane (selection) and engage the gear (engagement). The transmission computer watches every actuator through position sensors. In the hydraulic versions, one sensor reads the accumulator pressure so the computer knows when to run the pump.

That sensor gets a 5 volt reference and a ground from the computer and sends back a signal somewhere between roughly 0.5 and 4.5 volts. The P0936 code is stored when that signal cuts out or jumps around. An intermittent break almost always comes down to a loose connection or a wire that is damaged inside its insulation.

When the signal is unreliable, the pump may run with no control at all or may not run when it should, and the gearbox loses the pressure it needs to shift. After any repair on these parts, the gearbox learning procedures (clutch touch point, selection positions and engagement positions) have to be run with a scan tool. Without them the transmission will not work properly.

Intermittent faults are found by making them happen. With the engine running and the scan tool in graph mode, move the wiring harness one section at a time, tap the connector lightly and, if needed, warm the area with a hair dryer or mist the connector with water. The spot where the reading jumps is where the fault is.

P0936 code symptoms

• Check engine light on.
• Loss of hydraulic pressure, or a pump that runs without control.
• The pump runs all the time, or you cannot hear it at all.
• The gearbox will not shift.

Likely causes of the P0936 code

1. Loose connector contact. Pins that are loose or pushed back out of the housing.
2. Wire broken inside the insulation. It opens the circuit when the car vibrates.
3. Harness rubbing against moving or hot parts.
4. Sensor with an intermittent fault, often one that shows up only when it heats up.

How to diagnose the P0936 code step by step

1. Read the sensor value on the scan tool and compare it with what you expect to see.
2. Inspect the connector for corrosion, water or loose pins.
3. Check the supply and ground with the key on: the reference should be correct and the ground should drop less than 0.1 volt.
4. Measure the signal with the connector plugged in and watch whether it changes with the operating condition.
5. Do the wiggle test on the harness with the scan tool in graph mode.
6. Check continuity of each wire back to the computer, which should be under 1 ohm.
7. Check the hydraulic fluid level in the reservoir.

How to fix the P0936 code

• Repair the connector or the wiring.
• Replace the sensor if the tests point to it.
• Fix the real condition if there is one, such as low fluid.
• Clear the P0936 code, run the learning procedures and confirm with a road test.

Technical reference data

• 5 volt reference, ground and a signal that follows the pressure (roughly 0.5 to 4.5 volts).
• Maximum ground voltage drop: 0.1 volt. Wire continuity: under 1 ohm.
• Reference values only: check the manufacturer data for your vehicle.

Brand-specific notes

This family of transmissions shows up again and again in a few makes. In many hydraulic systems the actuator fluid is a specific one, and the reservoir should be checked on a regular schedule.

P0936 on Opel

Very common on the Opel Easytronic.

P0936 on Fiat

Very common on the Fiat Dualogic.

P0936 on Toyota

Very common on the Toyota MMT.

P0936 on Smart

Very common on Smart models fitted with this type of gearbox.

P0936 on BMW

Very common on the BMW SMG.

Frequently asked questions about P0936