P0933Generic code

P0933 Code: Hydraulic Pressure Sensor Circuit Range/Performance

The P0933 code means the hydraulic pressure sensor gives a reading that is electrically valid but does not match what the computer expects. The main effect is lost pressure or a pump running with no control. Compare the sensor reading against the real pressure to find the fault.

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 P0933 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. The P0933 code is a range fault, which means the sensor is measuring but measuring wrong, or that a real abnormal condition exists.

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.

This kind of fault is not usually solved with a multimeter, because electrically everything looks correct. You have to compare what the part reports with reality: use a pressure gauge, a thermometer or a tachometer, or command the component with the scan tool and watch whether the physical result matches the order.

P0933 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 P0933 code

  1. Degraded or out-of-calibration sensor. It gives believable but wrong readings.
  2. Real abnormal condition. The system is actually working outside normal limits.
  3. High resistance in the connector from corrosion, which shifts the reading.
  4. Damaged or clogged port, hose or tone wheel, depending on the type of sensor.

How to diagnose the P0933 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 P0933 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.
  • 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.

P0933 on Opel

Very common on the Opel Easytronic.

P0933 on Fiat

Very common on the Fiat Dualogic.

P0933 on Toyota

Very common on the Toyota MMT.

P0933 on Smart

Seen on Smart vehicles with an automated manual transmission.

P0933 on BMW

Very common on the BMW SMG.

Frequently asked questions about P0933

Can I drive with a P0933 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 P0933?
As a rough guide, between $60 and $500. A connector cleanup is at the low end, and a new sensor costs more.
What does the P0933 code mean?
The P0933 code is a generic OBD2 code that means the hydraulic pressure sensor gives an implausible reading, one that is electrically valid but does not match what the computer expects.
Will a P0933 code clear itself?
Not usually. A drifting sensor or a corroded connector keeps giving bad readings, so the code returns.
What is the most common cause of P0933?
A degraded or out-of-calibration sensor, or high resistance in a corroded connector that shifts the reading.

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