Diagnosis using Fiat/Lancia tester

ECU input/output may be subjected to diagnosis whereby signal characteristics are checked cyclically. In the case of malfunction, errors are memorised in two tables: "current" and "history", the former associated with the volatile memory (RAM) and the other to the non-volatile memory (RAM STAND-BY).

When an error is recorded, it is saved in the "current" table and then input into the "history" table following a validation period.

When the error disappears, it is eliminated from the volatile memory but remains present in RAM STAND-BY.

For errors to be deleted from the non-volatile memory, one of the following conditions must be satisfied:

• - the number of error-free engine ignitions must exceed 20;
• - a special command is sent from the Fiat/Lancia Tester.

The RAM STAND-BY is cleared completely by the diagnostic instrument.

This strategy is usually applicable; the only exception occurs in the case of faults in injectors, phonic wheel and coils that are identified only when activated.

The diagnostic instrument can activate individual components in order to check their efficiency.

The presence of a sensor/actuator operating anomaly is indicated to the user by the lighting up of a warning light as soon as the fault occurs and this is simultaneously validated by the ECU itself (simultaneous memorisation in RAM and RAM STAND-BY);

The light goes off when the repair is carried out or if the fault is not permanent.

In the case of a fault, the ECU controls alternative functions in order to keep the engine working as far as possible so that the vehicle can be taken back to a service centre (recovery).

NOTE When the ignition is turned to "MAR" the warning light is on; it goes off some 0.5 sec. after a successful starting attempt if no significant faults are recorded.

Diagnosis using Fiat/Lancia tester

The F.L.T. should be connected to a bidirectional diagnostic socket in the engine bay on the relay cover

The TESTER should be connected to the electronic control unit as follows:

1. Connect the Fiat-Lancia Tester using «ADAPTER ADT 101 A»
2. Activate the TESTER through the cigar lighter socket or by connecting directly to the battery (a special lead is provided for this purpose).
3. Connect the TESTER socket to the ECU socket

The instrument is able to provide the following information:

• - Display engine parameters
• - Display errors
• - Active diagnosis
• - Memory to be used M 33-A