Today we have solved a case that we would like to share with you, as it was caused by misuse on the part of the driver and not by an actual fault.

The customer complained that the car would not start when the clutch was depressed, with the Stop and Start function engaged.

The message 'Start&Stop not available' appeared on the instrument panel display with the corresponding light on; engine restart was only possible via the key.

The following errors were detected in the engine ecu diagnosis:

- P0512: Plausibility check starter motor signal/relay motor control module

- B1081: start and stop relay control

Checks carried out: 

-20A fuse F 03 in the engine compartment control unit, of the starting consent relay T20: in order.

-Presence of open circuit on supply line +30: in order.

-Presence of a short circuit to ground on the +50 supply line: no short present.

In general, no errors detected.

We then ascertained from talking to the customer that the problem was caused by incorrect use on his part when restarting the engine. In fact, he was using the key to start the engine at the same time while the engine was already restarting autonomously by depressing the clutch and then by the Start&Stop device command.

We therefore explained to the customer that the Start&Stop strategy manages, by depressing the clutch pedal, both the restart after regular shutdown managed by the device itself, and the restart after an accidental engine stall, and that in any case, the engine must never be restarted with the key while the Start&Stop function is operational.

This example teaches us that it is very important to have a dialogue with the customer to understand what symptoms have been detected, so that we can make a preliminary diagnosis and avoid anomalies apparent.

Best regards

Antonio

PS: the errors were cleared with a diagnostic tester, without any problems.