303-06A Starting System - 1.6L Duratec-16V Ti-VCT (88kW/120PS) - Sigma 2014 Fiesta
Description and Operation Procedure revision date: 04/25/2013

Starting System - Vehicles With: Keyless Entry and Push Button Start - System Operation and Component Description

System Diagram

System Operation

Network Message Chart

  Module Network Input Messages Powertrain Control Module (PCM)


Broadcast Message Originating Module Message Purpose
Selector lever (PRNDL) status   TCM Provides the PCM with the selector lever status. The PCM only energizes the starter relay if the selector lever is in PARK or NEUTRAL.
Crank request   BCM Provides the PCM with indication that the driver has commanded the engine to crank.
Power mode   BCM Provides the PCM with ignition mode.




  Module Network Input Messages Body Control Module (BCM)


Broadcast Message Originating Module Message Purpose
Intelligent access system status RFA module The response from the BCM request for the RFA module ID. If the RFA module ID response is incorrect, then the PATS is disabled.


Push Button Start System

This vehicle is equipped with a PATS that disables the engine from cranking if an unprogrammed PATS key is used or an invalid PCM ID is received. The PATS is controlled by the BCM . If there is a PATS concern that causes the engine to be disabled, the IPC displays the corresponding message in the message center. For additional information,
Refer to: Passive Anti-Theft System (PATS) - System Operation and Component Description (419-01C Passive Anti-Theft System (PATS) - Vehicles With: Keyless Entry and Push Button Start, Description and Operation).

Ignition modes are controlled by the RFA module and the BCM . For additional information on the ignition switch - push button start modes,
Refer to: Steering Wheel and Column Electrical Components - System Operation and Component Description (211-05 Steering Column Switches, Description and Operation).

The ignition switch - push button start is connected to the RFA module and the BCM as a backup in case of a failure. If there is a circuit failure to either module from the ignition switch - push button start, the modules communicate the ignition switch - push button start request to each other over the Medium Speed Controller Area Network (MS-CAN).

During a start event the ignition switch - push button start is pressed in combination with either the brake pedal (automatic transmission) or the clutch pedal (manual transmission) input. The RFA module, the BCM and the PCM receive a request to start the engine. The PCM recognizes the correct inputs and provides voltage and ground to energize the starter relay coil and close the starter relay contacts. The starter relay contacts close, providing voltage to the starter solenoid, allowing the starter motor to crank the engine. The PCM disengages the starter motor once an engine Revolutions Per Minute (RPM) threshold is reached, a set crank time is exceeded or the ignition switch - push button start is pressed indicating an engine shutdown.

Component Description

Body Control Module (BCM)

For more information,
Refer to: Passive Anti-Theft System (PATS) - System Operation and Component Description (419-01C Passive Anti-Theft System (PATS) - Vehicles With: Keyless Entry and Push Button Start, Description and Operation).

Passive Key

For more information,
Refer to: Passive Anti-Theft System (PATS) - System Operation and Component Description (419-01C Passive Anti-Theft System (PATS) - Vehicles With: Keyless Entry and Push Button Start, Description and Operation).

Ignition Switch - Push Button Start

The ignition switch - push button start is a momentary contact switch that is hardwired to the RFA module. The ignition switch - push button start is used to obtain the OFF, ON or START ignition modes. For more information,
Refer to: Steering Wheel and Column Electrical Components - System Operation and Component Description (211-05 Steering Column Switches, Description and Operation).

Remote Function Actuator (RFA) Module

For more information,
Refer to: Passive Anti-Theft System (PATS) - System Operation and Component Description (419-01C Passive Anti-Theft System (PATS) - Vehicles With: Keyless Entry and Push Button Start, Description and Operation).

Powertrain Control Module (PCM)

The PCM provides power and ground to the start relay to initiate cranking of the engine.