Checking idle speed

Checking idle speed

Check that the idle speed is correct.

Tests with FIAT/LANCIA Tester

Guided fault finding on the electrical part can be conducted by connecting the FIAT/LANCIA Tester with M39-A memory to the control module's diagnostic socket.

Full diagnosis of the system consists of three stages:

1. display of a set of operating parameters (with the engine running);
2. display of errors and elimination of the causes (guided diagnosis);
3. activation of the actuators (active diagnosis).

1. Display of operating parameters

The following operating parameters are displayed:

• selector lever position;
• gear engaged;
• vehicle speed;
• throttle valve angle of aperture;
• STH pressure control solenoid;
• kick-down switch,
• brake pedal contact;
• engine coolant temperature;
• gearbox oil temperature;
• gearbox main shaft rpm;
• driving torque reduction function;
• battery voltage.

2. Display of errors and elimination of causes (guided diagnosis)

At the beginning of diagnosis, the F/L Tester reads the errors memorized by the control module. When an error is detected, the F/L Tester emits an acoustic signal and displays a message relating to the error.

A list of the possible causes of the error is then displayed.

After all the necessary repairs or replacements have been carried out and all the faults eliminated, the errors will be automatically deleted by the F/L Tester.

Guided diagnosis can also be carried out by checking step by step the efficiency of the circuits and operation of the various sensors/switches.

Once the faults have been eliminated, a road test should be carried out with the engine and gearbox up to temperature for at least 10 minutes, and then the F/L Tester should be used to check that there are no faults in the system.

3. Activation of actuators (active diagnosis)

The following actuators can be activated by a command sent from the F/L Tester, with the engine off and the selector lever at position N:

• gear change solenoids S1 and S2;
• lock-up clutch control solenoid SL;
• line pressure control solenoid STH.

This test is useful for checking the operation of the actuators, as the ticking caused by the internal movement of the solenoids can be heard.

Errors memorized by the control module can also be deleted under active diagnosis (provided they are no longer present or the conditions are not recreated).

NOTE Errors can also be deleted by disconnecting the battery for over 10 seconds.