Diagnostics of automatic transmission pressure sensor AL4
Materials:
* OBD-II scanner
* Multimeter
* Pressure gauge (optional)
Steps:
1. Reading Trouble Codes (DTC)
* Connect the OBD-II scanner to the vehicle’s diagnostic connector.
* Turn on the ignition.
* Select “Read fault codes”.
* Find codes related to automatic transmission pressure.
2. Visual inspection
* Inspect the sensor electrical connector for any signs of corrosion, damage, or loose connections.
*Check whether the connector is tightly connected.
3. Checking the supply voltage (select models only)
* Set the multimeter to the DC voltage scale.
* Disconnect the electrical connector of the sensor.
* Connect the red probe to the power pin on the connector.
* Connect the black probe to the ground terminal.
* Turn on the ignition.
*Measured voltage should be between 5-12V.
4. Resistance measurement (select models only)
* Set the multimeter to the resistance scale.
* Disconnect the electrical connector of the sensor.
* Connect the red probe to the signal pin on the connector.
* Connect the black probe to the ground terminal.
* Measured resistance should be between 500-5000 ohms.
5. Checking the output signal (select models only)
* Connect a pressure gauge to the cooling system test port.
* Set the multimeter to the DC voltage scale.
* Connect the red probe to the signal pin on the sensor connector.
* Connect the black probe to the ground terminal.
* Set the engine to idle speed and gradually increase the speed.
* The measured voltage should increase with increasing pressure.
Interpretation of results:
* If all checks pass, the automatic transmission pressure sensor is most likely working.
* If any test fails, the sensor or its electrical connections may be faulty.
* If DTCs related to automatic transmission pressure are detected, perform the appropriate diagnostic steps to determine the exact cause of the problem.