This vehicle is equipped with a body control module (BCM).
The BCM performs multiple body control functions. The following vehicle systems
are directly connected to the BCM:
• | The audible warnings system |
• | The interior lighting system |
• | The keyless entry system |
• | The content theft deterrent system |
These systems are controlled by the BCMs outputs. The BCM controls its
outputs based upon the input information obtained from the sensors and switches
that are directly connected to the BCM. The BCM evaluates the input
information and controls the body systems by commanding an output on
or off.
This vehicle is equipped with 1 of 4 types of BCMs. The
BCM type installed on this vehicle is based on the vehicle equipment content
and options. The following are the 4 types:
• | BCM type 2E (export vehicles) |
Refer to Entering The Feature Customization Mode for more information
on how to identify the BCM type installed.
BCM Type 2
The BCM type 2 provides audible warnings, interior lighting and
automatic power door locks.
BCM Type 2E
The BCM type 2E provides all of the features of the BCM Type 2
plus an overspeed warning. The BCM type 2E is installed on export vehicles
only.
BCM Type 3
The BCM type 3 provides all of the features of the BCM type 2,2E
plus keyless entry. Vehicles with RPO AU0 are equipped with a BCM type 3.
BCM Type 4
The BCM type provides all of the features of the BCM type 2,2E
and BCM type 3 plus content theft deterrent. The vehicle with RPO AU0
and UA6 are equipped with a BCM type 4.
Body Control Module (BCM) Features
Based on the vehicle equipment/options, the body control module (BCM)
controls these vehicle systems:
• | The automatic door locks |
• | The keyless entry (BCM type 3 and BCM type 4) |
• | The content theft deterrent (BCM type 4) |
Audible Warnings
The following are components with audible warnings:
• | The key in the ignition reminder |
• | The fasten seat belt reminder |
• | The fasten belts indicator control |
• | The turn signal reminder |
• | The driver information display reminder |
• | The trip calculator reminder |
• | The headlamps ON reminder |
• | The last door closed locking confirmation |
• | The overspeed warning (export vehicles) |
• | The feature customization and diagnostics feedback |
Refer to
Audible Warnings Circuit Description
in Instrument Panel, Gauges and Console for more
information.
Interior Lighting
The following are the areas of interior lighting:
• | The interior illumination control |
• | The delayed illumination |
• | The door key unlock illumination (BCM type 4 only) |
• | The keyless entry unlock illumination (BCM type 3 and BCM
type 4 only) |
• | The inadvertent load (battery rundown) protection |
• | The feature customization of interior lighting modes, delayed
illumination and exit lighting |
Refer to
Interior Lights Circuit Description
in Lighting Systems for more information.
Automatic Door Locks
The BCM type 2,2E have the following automatic door lock features:
• | The last door closed locking |
• | The lockout prevention override |
• | The ignition OFF unlock |
• | The shift into PARK unlock |
• | The shift out of PARK lock |
• | The sliding door delayed locking |
The BCM type 3 has the following automatic door lock features
in addition to the BCM type 2,2E features:
• | The remote driver door unlock |
• | The remote all door unlock |
• | The remote all door lock |
The BCM type 4 has the key cylinder unlock/lock automatic door
lock feature in addition to the BCM type 2,2E and BCM type 3
features.
The BCM provides the feature customization of the following door lock
functions:
• | The shift out of PARK lock |
• | The ignition OFF unlock |
• | The shift into PARK unlock |
• | The last door closed locking |
Keyless Entry
The BCM type 3 provides the following keyless entry features:
• | The remote driver door unlock |
• | The remote all door unlock |
• | The remote all door lock |
• | The remote activation verification (BCM type 4) |
• | The remote alarm (BCM type 4) |
• | The feature customization of the remote unlock control and remote
activation verification |
Content Theft Deterrent
The BCM type 4 features a content theft deterrent system which
is designed to deter vehicle vandalism and theft. The content theft deterrent
system perform the following functions:
• | Flashes the exterior lights |
• | Disables fuel delivery to the engine |
The BCM monitors the status of the following components:
• | The keyless entry system |
The BCM operates the following components according to the mode of system
operation:
• | The security indicator lamp |
The BCM communicates a fuel enable signal to the Powertrain Control
Module (PCM) when the system is disarmed.
The BCM also provides feature customization of the following modes.
Refer to
Content Theft Deterrent (CTD) Circuit Description
in Theft Deterrent for more information:
• | The theft deterrent mode |
The body control module (BCM) provides diagnostics to assist
service technicians during troubleshooting. The BCM has the following diagnostic
capabilities when entering the diagnostics mode:
• | Diagnostic trouble codes (DTCs) |
Entering The Feature Customization Mode
When performing the BCM diagnostics, enter the feature customization
mode. During this mode the BCM identifies itself. This ensures that both
of the vehicles option content match with the BCM capabilities. In order
to enter the feature customization mode perform the following steps:
- Turn the ignition switch to the LOCK position.
- Remove the BCM PRGRM fuse.
- Turn the ignition switch to the ACC position.
Upon entering the feature customization mode, the BCM flashes the fasten
belts indicator and sounds the chime 2, 3 or 4 times which is equal to the
BCM type used on the vehicle. Ensure that the BCM installed on the vehicle
is compatible with all of the features on the vehicle. If not, then
replace the BCM with the proper type.
The following vehicle systems have features that can be customized:
• | Content Theft Deterrent |
Entering The Diagnostics Mode
Complete the following steps in order to enter the diagnostics mode:
- Ensure the BCM is in the feature customization mode.
- Turn the ignition switch from the ACC position to the LOCK position,
then back to the ACC position within 1 second.
Complete the following procedure in order to confirm the BCM has entered
the diagnostics mode:
- Ensure that all of the vehicle doors are closed.
- Open and close any vehicle door.
- Fasten and release the driver seat belt.
The BCM sounds the chime when receiving an input signal such as opening
a door or fastening the driver seat belt when the BCM is in the diagnostics
mode.
If the BCM does not sound the chime upon opening a door or fastening
the driver seat belt, repeat Step 1 of Entering the Feature Customization
Mode. If the BCM does not enter the diagnostics mode, then refer to
Diagnostic System Check - Body Control System
Upon entering the diagnostics mode, the BCM flashes the fasten belts
indicator and sounds the chime a number of times equal to the DTCs stored
in the memory. If no DTCs are stored, the BCM does not flash the fasten
belts indicator or sound the chime.
The BCM flashes and sounds the first DTC with the lowest number, pauses,
then continues with the next DTC with a higher number until all the DTCs are
read. Once all the DTCs are read, the BCM repeats this sequence 3 times.
If there are DTCs in the memory, record the DTCs and refer to Identifying
Diagnostic Trouble Codes.
Identifying The Diagnostic Trouble Codes
DTC
| Definition
|
1
| Fasten belt indicator lamp control circuit shorted to
B+ or ground
|
2
| Power output circuit to courtesy lamps shorted to B+
or ground
|
3
| Courtesy lamps ground control circuit shorted to B+
|
6
| Theft deterrent relay control circuit shorted to B+ or ground
|
7
| Horn relay control circuit shorted to B+ or ground
|
8
| RFA link circuit open or shorted to B+ or ground
|
In order to erase the DTCs stored in the BCM press and hold the UNLOCK
button on either power door lock switch for 4 seconds while the BCM
is in the Diagnostics Mode.
Entering The Input/Output Test
After the BCM reads all the DTCs in the memory, the BCM enters the Input/Output
test.
The BCM flashes the fasten belts indicator and sounds the chime once
when operating one of the following inputs:
• | All the reading courtesy lamp switches |
• | The door lock cylinders |
• | The driver door lock ajar switch |
• | The driver fasten seat belt switch |
• | The driver information display (DID) |
• | The headlamps OFF switch |
• | The IP compartment lamp switch |
• | The keyless entry requests for door lock/unlock |
• | The keyless entry requests for the alarm (RPO UA6) |
• | The passenger door lock ajar switch |
• | The power door lock switches |
• | The liftgate ajar switch |
• | The sliding doors jamb switch(es) |
• | The sunshade illuminated mirrors |
If the BCM does not provide a chime feedback then there is an open or
short in the circuit or a faulty component.
Perform the following procedure in order to test the BCM outputs:
- Ensure that the BCM is in the diagnostics mode
- Turn the IP dimmer switch to the DOME position
The BCM enters the output test. The output test includes the following
tests:
• | Test 1-- De-energizes CKT 1993. Turn off all of the
interior lamps. |
• | Test 2-- Energizes CKT 1393. Provides power to all
of the interior lamps. |
• | Test 3-- Grounds CKT 690. Turns on all of the courtesy
lamps. |
• | Test 4-- Energizes the theft deterrent relay for 1 second
by grounding CKT 352. Turns on all of the headlamps (BCM type 4
only). |
• | Test 5-- Energizes the horn relay for 25 ms by grounding
CKT 28. Sounds the horn (BCM type 4 only). |
• | Test 6-- Turns on the theft deterrent indicator lamp by grounding
CKT 749 (BCM type 4 only). |
• | Test 7-- Turns off the theft deterrent indicator lamp by
opening CKT 749 (BCM type 4 only). |
The BCM operates the output test in numerical order.
In order to move to the next test, cycle the IP dimmer switch from the
dome position, to OFF then back to DOME. The BCM sounds the chime a number
of times equivalent to the output test number above.
Exiting Diagnostics
Perform the following procedure in order to exit the BCM diagnostics
mode and return to normal BCM operation:
- Turn the ignition switch to the LOCK position.
- Reinstall the BCM PRGRM fuse.
- Turn the ignition switch to the RUN position.