Savana 3500 V8-6.6L DSL Turbo VIN 6 (2007)
Keyless Starting System: Technical Service Bulletins
Remote Starting System - System Inoperative Diagnostics
INFORMATION
Bulletin No.: 08-08-52-002
Date: February 27, 2008
Subject:
Diagnostic Information for Inoperative Remote Vehicle Start
Models:
2005-2008 GM Passenger Cars and Light Duty Trucks (including Saturn)
2005-2008 HUMMER H2
with Remote Keyless Entry RPOs AP3 or AP8
Remote Vehicle Start (RVS) Inoperative Diagnostic Concerns
Information on Hood Latch Switches
One of the many components involved in the Remote Vehicle Starting System is the Hood Latch Switch. The state of this switch is checked by the BCM
during a remote vehicle start request and the component must function properly in order for the vehicle to commence a remote start event. During the
infancy of this option (RPO AP3/AP8) parts return analysis showed a significantly shorter than expected component life for the Hood Latch Switch
shared across many different GM vehicles.
The switches currently being factory installed, and sent as service replacement parts, are vastly improved in design and suitably robust. Most hood latch
switches currently returned under warranty are analyzed and determined to have no trouble found (NTF). It is understandable and desirable that
technicians gain familiarity with the vehicles they service on a daily basis, however it is required that technicians follow Strategy Based Diagnostics
before replacing this switch.
Important:
The ONLY way to repair or replace a hood latch switch is to replace the LATCH ASSEMBLY. The switch CANNOT be serviced separately from
the latch and is NOT AVAILABLE from GMSPO. Any effort to remove the switch from the latch will permanently damage the switch and void the
warranty coverage of that part.
Important:
The hood switch provides status of the hood to the BCM for RVS purposes. The switch is integrated into the hood latch assembly. The hood ajar
switch provides two separate inputs to the BCM. These separate inputs allow the BCM to actively monitor for a hood ajar switch fault.
RVS System Operation
The remote vehicle start (RVS) function allows engine starting while not in the vehicle. It also allows the vehicle HVAC system and other vehicle
systems to enable providing a comfortable vehicle upon entry. RVS functions have an operating range of up to 59 m (195 ft) depending on conditions.
The RVS sequence begins by pressing and releasing the lock button and then pressing and holding the RVS buttons on the keyless entry transmitter. The
turn signal lamps will illuminate to indicate the vehicle has received the remote start request. Each time an RVS is performed the vehicle doors are
locked; however they may then be unlocked/locked with the transmitter or vehicle key at any time. Once activated the engine is allowed to run for 10
minutes. The RVS time may be extended by an additional 10 minutes by again pressing and releasing the lock button and then pressing and holding the
RVS buttons on the transmitter. This feature is called an RVS continue and allows a maximum of 20 minutes of engine running. If the RVS continue is
performed at 7 minutes into the initial 10 minute time-out a total of 17 minutes of engine running would occur. The RVS event may be suspended at any
time by pressing only the RVS button on the transmitter or by entering the vehicle and turning ON the hazard lamps.
RVS System Description
Remote vehicle start (RVS) begins as a Radio Frequency (RF) message received by the remote control door lock receiver (RCDLR) from a keyless entry
transmitter. The RVS request is sent by the RCDLR to the body control module (BCM) via serial data line. The BCM monitors system conditions such
as content theft deterrent (CTD) closures ajar status and body DTCs to determine if an RVS event will occur. If conditions are determined to be
acceptable the RVS message is sent to the engine control module (ECM). The ECM monitors system conditions such as engine control parameters and
vehicle theft deterrent (VTD) to determine if engine starting will be allowed. If conditions are acceptable the ECM will initiate engine starting. During
