Checking the engine speed signal
Start the engine.
Check the voltage between terminal 2 of the ACM control unit and «weight».
- Voltage at idle speed: approx. 4.5V
- Voltage at 2000/min: Approx. 4.0V
In the event of a malfunction, check the following:
- Input circuit
- instrument cluster
- Damage or tight connection of the connectors of the ACM control unit.
Range switch signal test
Turn the ignition key to the ON position (without starting the engine).
Check the voltage between terminal 3 of the ACM control unit and «weight».
Voltage:
- In position P or N: approx. 0V
- In other positions: approx. 12V
In the event of a malfunction, check the following:
- Input circuit
- Range switch
- Damage or tight connection of the connectors of the ACM control unit.
Checking the load cell signal
The signal voltage is very low. In order to avoid an incorrect assessment of the health of the sensor, it is recommended to check it with the CONSULT tester.
Check the operation of the sensor as follows.
Adjust the vibration level, see above. Make sure that the tone of the sound of the drives changes smoothly (check the drive from the front first, then from the rear). In the event of a load cell or actuator failure, the tone does not change and the vibration level control stops.
In the event of a malfunction, check:
- Sensor input circuit and circuit «masses».
- Damage or tight connection of the connectors of the ACM control unit.
Load cell test
Check the resistance between contacts 1-2, 1-3, 2-3 of the sensor.
- Resistance: 10 M Σ - infinity Σ