Failed Engine Cut Out Conditions; Conditions Managed By The Ecm - Fiat TIPO 2015 Mode D'emploi

When the engine is started, both relays are closed. At the end of starting, the engine management
module opens relay R2 and immediately afterwards orders brief closure of the same relay to diagnose
the body computer relay: if the voltage level downstream of the relay is low, relay R1 has not become
stuck. If instead the level is high, relay R1 has become stuck. A fault code will be set and the
Stop/Start is disabled.
Starting by Stop/Start occurs according to the same logic as key starting, with the sole difference that
the starting signal (+50) arrives at the BCM from the CAN and not from the switch.
In normal conditions, both relays are controlled only when the engine is started, both by key and by
Stop/Start.

Failed engine cut out conditions

Conditions managed by the ECM

When the Stop/Start is activated, under certain circumstances the engine does not stop
automatically due to comfort, emission control and safety reasons.
These conditions leading to a failed automatic engine cut-out can be detected and managed by the
BCM or by the ECM.
Engine cold: the automatic engine cut-out is not allowed if the signal from the engine coolant
temperature sensor is outside of a range from Temp_H20_min (about 40°C) and Temp_H20_max.:
(about 100°C). In this case the consumption and emission reduction derived from the Stop/Start is
not guaranteed. Refer to the table in the appendix for the details.
Reverse engaged: if reverse gear is engaged, the Powertrain Control Module does not allow the
automatic stopping of the engine. In this way the driveability during parking manoeuvres is not
compromised.
Clutch switch operation check not performed yet : This check takes place following a complete
clutch pedal cycle (release and pressing or pressing and release) with the engine on.
Malfunction or fault detected in at least one of the following sensors or systems:
Accelerator pedal.

Brake pedal.

Vacuum sensor on brake servo.

 Gearbox control unit.
 Water temperature sensor in the engine.
Wheel speed sensors.

Clutch switch.

Engine rpm sensor.

Camshaft sensor.

Reverse switch.

Engine or Powertrain Control Module (with MIL on).

Braking system low vacuum: the ECM prevents the automatic engine cut-out if the

vacuum sensor (see paragraph on the sensors detected by the ECM for details on the
sensors) transmits a LOW value.
The BCM asked to prevent the engine automatic stopping by sending a C_CAN

message if one or more conditions managed by the BCM occur.
For Diesel engines only. Particulate filter regeneration in progress; the Powertrain Control Module
does not allow the automatic engine cut-out if the DPF is carrying out the regeneration of the filter.
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FIAT TIPO -54- 0.0
REV