Principles of Operation

Starting System

Principles of Operation

NOTE: This vehicle is equipped with Passive Anti-Theft System (PATS) that disables the engine from cranking and starting if an unprogrammed PATS key is used or an invalid PCM ID is received. PATS is controlled by the Body Control Module (BCM). If there is a PATS concern that causes the engine to disabled, the Instrument Panel Cluster (IPC) displays "STARTING SYSTEM FAULT" in the message center. Refer to Anti-Theft - Passive Anti-Theft System (PATS) Testing and Inspection to diagnose a PATS concern.

The starting system is electronically controlled by the PCM. The PCM receives the following inputs:

- PATS enable status from the BCM
- Correct transmission PARK or NEUTRAL input from the Transmission Range (TR) sensor
- Request to start the engine, ignition switch in the START position

Under normal operation when the ignition is turned to the START position, the BCM generates a key verification message. It sends this message to the PATS transceiver. The transceiver reads the key and sends a key verification message back to the BCM. If the message received does not match the key verified in the BCM memory, the engine is disabled and does not crank and start. Once the BCM determines the correct programmed key is in the ignition, the BCM sends the PCM a valid PATS message. When the PCM receives the message, it generates a response and sends it back to the BCM. If the response from the PCM does not match the response in the BCM memory, PATS is not enabled and the engine does not crank. If both the key verification and PCM ID pass, PATS is enabled. The PCM recognizes the correct electronically coded passive key and provides voltage and ground to the starter relay coil. The starter relay coil is energized causing the relay contacts to close providing voltage to the starter solenoid, allowing the starter motor to crank and start the engine. The PCM disengages the starter once an engine rpm threshold is reached, a set crank time is exceeded or the ignition is turned OFF.

The TR sensor prevents operation of the starter motor unless the transmission is in NEUTRAL or PARK.

Remote Start

The factory remote start system (if equipped) does not operate if the ignition is in the RUN/START position or the hood is not closed.

The remote start system can be enabled or disabled by the customer. When enabled, the customer can set the engine run time for 5, 10 or 15 minutes. For information on setting the engine run time, refer to the Owner's Literature or Instrumentation, Message Center, and Warning Chimes Testing and Inspection.

The remote start system enables the engine to be started from up to 100 m (328 ft) away, by pressing a sequence of buttons on the Integrated Keyhead Transmitter (IKT). The remote start system is activated by pressing the lock button on the IKT, to make sure the doors are locked, followed by 2 presses of the remote start button. The 3 button presses must occur within 3 seconds. The system acknowledges the start request by flashing the exterior lights twice. Once started, the engine runs for 10 minutes (default run time is 10 minutes; the time can be programmed by the customer to 5, 10 or 15 minutes) and the parking lights remain illuminated until the cycle is complete. The remote start duration can also be extended by initiating remote start while the first timer is still running or by initiating a completely independent start cycle when the first has completed. No more than 2 remote start sequences can occur within a one hour period, unless the ignition is set to the RUN/START position between the remote start requests. During the remote start cycle the power windows are inhibited and the radio will not turn on automatically but may be switched on manually from inside the vehicle. If the remote start system fails to start the horn chirps twice.

To transition from remote start mode to drive mode, use a programmed IKT to switch the ignition to the RUN position. If a programmed IKT is not used, the engine shuts off.

To deactivate the remote start system, press the remote start button once. When deactivating the remote start system the parking lights turn off to give a visual indication that the engine and climate control features have turned off. It may be necessary to be closer to the vehicle to deactivate the remote start feature than it was to initiate it due to ground deflections and added noise from the engine running.

The remote start system conditions the cabin temperature during remote start based on the outside temperature. For information on cabin temperature conditioning during remote start, refer to Climate Control System - General Information and Diagnostics Testing and Inspection.