P0935Generic code

P0935 Code: Hydraulic Pressure Sensor Circuit High

The P0935 code means the hydraulic pressure sensor signal is above its maximum value. The main effect is lost pressure or a pump running with no control. Look for an open circuit, an interrupted ground or a loose connector.

Severity
High
Can I keep driving?
Yes, but with caution
Estimated cost
$60 to $500
Difficulty
Medium
System
Transmission
Applies to
All OBD2 vehicles

Updated Reviewed by Renzo Chacca

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What the P0935 code means

Automated manual transmissions (Opel Easytronic, Fiat Dualogic, Toyota MMT, BMW SMG, Ford Durashift, Volkswagen ASG) and many dual clutch transmissions use electric or hydraulic actuators to disengage the clutch, to choose the gear plane (select) and to engage the gear (shift). The transmission computer watches every actuator with position sensors. On hydraulic systems, a sensor measures accumulator pressure so the computer can control the pump.

The sensor gets a 5 volt reference and a ground from the computer and sends back a signal between about 0.5 and 4.5 volts. A high signal, which is what the P0935 code reports, is usually caused by an open circuit or an interrupted ground.

If the signal fails, the pump can run with no control or fail to switch on, and the transmission loses the pressure it needs to shift. After any repair of these components you must run the transmission relearn procedures with a scan tool (clutch touch point, select and shift positions). Without them the transmission will not work properly.

To confirm the fault, measure the continuity of each wire between the component connector and the computer connector with the key off. It should be under 1 ohm, and an infinite reading means the wire is open. If the wiring is good, measure the component itself. An infinite resistance confirms it is open inside.

P0935 code symptoms

  • Check engine light on.
  • Pressure loss, or a pump running with no control.
  • The pump runs constantly or cannot be heard at all.
  • The transmission does not shift.

Likely causes of the P0935 code

  1. Loose or broken connector. The most frequent cause.
  2. Cut signal or ground wire. The signal rises up to the reference voltage.
  3. Sensor open inside. The resistance reads infinite.
  4. Short to 5 volts or 12 volts from rubbing against another wire in the harness.

How to diagnose the P0935 code step by step

  1. Read the sensor value on the scan tool and compare it with what you expect.
  2. Inspect the connector for corrosion, water or loose pins.
  3. Check supply and ground with the key on: the reference should be correct and the ground voltage drop under 0.1 volts.
  4. Measure the signal with the connector attached and see whether it changes with the condition.
  5. Do a wiring wiggle test with the scan tool in graphing mode.
  6. Check the continuity of each wire to the computer (under 1 ohm).
  7. Check the hydraulic fluid level.

How to fix the P0935 code

  • Repair the connector or the wiring.
  • Replace the sensor if the tests confirm it is bad.
  • Correct the real condition if one exists.
  • Clear the codes and verify with a road test.

Technical reference data

  • 5 volt reference, ground and a signal proportional to pressure.
  • Wire continuity between connectors: below 1 ohm.
  • Approximate values only: check the manufacturer data for your vehicle.

Brand-specific notes

This code is very common on automated manual transmissions. On many hydraulic systems the actuator fluid is a specific type and the reservoir should be checked regularly.

P0935 on Opel

Very common on the Opel Easytronic.

P0935 on Fiat

Very common on the Fiat Dualogic.

P0935 on Toyota

Very common on the Toyota MMT.

P0935 on Smart

Seen on Smart vehicles with an automated manual transmission.

P0935 on BMW

Very common on the BMW SMG.

Frequently asked questions about P0935

Can I drive with a P0935 code?
Yes, with caution. Pressure problems can leave the transmission unable to shift, so keep trips short.
Do I have to replace the sensor?
Only if the tests confirm it. The connector and the wiring fail just as often as the sensor does.
What does the hydraulic pressure sensor do?
Automated manual transmissions (Opel Easytronic, Fiat Dualogic, Toyota MMT, BMW SMG, Ford Durashift, Volkswagen ASG) and many dual clutch units use electric or hydraulic actuators to release the clutch, select the gear plane and engage the gear. The computer watches each actuator with position sensors. On hydraulic systems, a sensor measures accumulator pressure so the computer can control the pump.
How much does it cost to fix P0935?
As a rough guide, between $60 and $500. A connector or wire repair is at the low end, and a new sensor costs more.
What does the P0935 code mean?
The P0935 code is a generic OBD2 code that means the hydraulic pressure sensor signal in an automated transmission is above its maximum value.
Will a P0935 code clear itself?
Only if the cause was a temporary glitch. A loose connector or a cut wire will bring it back.
What is the most common cause of P0935?
A loose or broken connector. A cut signal or ground wire and a sensor that is open inside come next.

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