Part 2 of 5

ORC/SIACM Diagnostic Trouble Codes
Airbag diagnostic trouble codes consist of active and stored codes. If more than one code exists, diagnostic priority should be given to the active codes. Each diagnostic trouble code is diagnosed by following a specific testing procedure. The diagnostic test procedures contain step-by-step instructions for determining the cause of the trouble codes. It is not necessary to perform all of the tests in this book to diagnose an individual code. Always begin by reading the diagnostic trouble codes using the DRB. Always begin diagnostic with the Table of Contents. This will direct you to the specific test(s) that must be performed. Active diagnostic trouble codes for the airbag system are not permanent and will change the moment the reason for the code is corrected. In certain test procedures, diagnostic trouble codes are used as a diagnostic tool.

Active Codes
The code becomes active as soon as the malfunction is detected or key-on, whichever occurs first. An active trouble code indicates an on-going malfunction. This means that the defect is currently there every time the airbag control module checks that circuit or component. It is impossible to erase an active code. Active codes automatically erase by themselves when the reason for the code has been corrected. With the exception of the warning lamp trouble codes or malfunctions, when a malfunction is detected, the airbag lamp remains lit for a minimum of 12 seconds or as long as the malfunction is present.

Stored Codes
Airbag codes are automatically stored in the ORC's memory as soon as the malfunction is detected. The exception is the Loss of Ignition Run Only code which is an active code only. A stored code indicates there was an active code present at some time. However, the code currently may not be present as an active code, although another code could be active. When a. trouble code occurs, the airbag warning indicator illuminates for 12 seconds minimum (even if the problem existed for less than 12 seconds). The code is stored, along with the time in minutes it was active, and the number of times the ignition has been cycled since the problem was last detected. The minimum time shown for any code will be one minute, even if the code was actually present for less than one minute. Thus, the time shown for a code will be one minute, even if the code was actually present for less than one minute. Thus, the time shown for a code that was present for two minutes 13 seconds, for example, would be three minutes. If a malfunction is detected a diagnostic trouble code is stored and will remain stored. When and if the malfunction ceases to exist, an ignition cycle count will be initiated for that code. If the ignition cycle count reaches 100 without a reoccurrence of the same malfunction, the diagnostic trouble code is erased and that ignition cycle counter is reset to zero. If the malfunction reoccurs before the count reaches 100, then the ignition cycle counter will be reset and diagnostic trouble. code will continue to be a stored code. If a malfunction is not active while performing a diagnostic test procedure, the active code diagnostic test will not locate the source of the problem. In this case, the stored code can indicate an area to inspect. If no obvious problems are found, erase stored codes, and with the ignition on wiggle the wire harness and connectors, rotate the steering wheel from stop to stop. Recheck for codes periodically as you work through the system. This procedure may uncover a malfunction that is difficult to locate.

AUDIO SYSTEM
The following radios are all on the PCI Bus system - RBB, RBK, RAZ, RAD, RBT, and RBY The remaining radio also available, the RAS, is NOT on the PCI Bus. The PCI Bus inputs into the radio are used for VF dimming, remote steering wheel controls and cabin EQ preference. PCI Bus outputs from the radio are used for the Name Brand Speaker (NBS) relay activation, as well as cabin EQ preference.

The RBB and RBK radios have the capability of containing multiple vehicle unique equalization curves (cabin EQ preferences) within the radio. These curves will reside in the radio's flash memory. The radio is capable of storing up to 20 unique equalization curves. The latent curves can be selected via the Front Control Module transmitting a PCI Bus message to the radio in response to a radio request for equalization message. Upon receipt of a valid equalization select message response, the radio will switch to output the corresponding equalization curve.

All the radios, except the RAS, are capable of displaying faults and allowing certain actuation tests through the use of the DRBIII(R). When attempting to perform PCI Bus diagnostics, the first step is to identify the radio in use in the vehicle.

When trouble shooting output shorts or "output" error messages, the following applies:

On radios without an external amplifier, the term output refers to the path between the radio and the speaker. This type of circuit can be monitored all the way through the speaker connections by the radio assembly. When the radio displays a shorted output DTC with this type of system, the speaker, radio, or wiring could be at fault. The output DTC could refer to the front or rear output or a left or right output. The reason for the difference is the pairing of the output sections of the radio. Some are paired left and right, others are paired front and rear.

On radios with an external amplifier, the term "output" refers to the circuit between the radio connector and the amplifier. The radio is capable of monitoring only this portion and can tell nothing about the circuit between the amplifier and the speakers. Consequently, a shorted output DTC on this type of system would only refer to this circuit. A faulty speaker could not cause this DTC.

Remote Radio Controls
These radios can be controlled via remote radio switches (optional). These switches are located on the back side of the steering wheel. They control mode, preset, seek up, seek down, volume up and volume down functions.

These functions are inputs to the Body Control Module and can be read with the DRBIII(R) under "body computer" then sensor displays. The switches are a multiplexed signal to the BCM. The radio control MUX circuit is a 5 volt line that is pulled to ground through different value resistors built into the switches. This causes a voltage drop to be seen by the BCM and it sends a specific message to the radio on the PCI Bus circuit. The radio then responses to the message.

This circuit is fairly simple to troubleshoot. The circuit must be complete from the switches in the steering wheel to the BCM. The ground must be complete so that the switches can cause the voltage drop for the BCM to see. The circuit passes through the clockspring so continuity through this devise must be verified.

CD Changer
The new in-dash CD Changer is designed to fit into the existing cubby bin in the center stack. This new cartridge-less CD Changer is controlled by your radio, and allows you to individually load up to four discs at a time. However, due to its compact design, the CD Changer can only carry out one operation at a time. For example, you can not load a new disc while playing another at the same time. Each operation happens sequentially.

The radio unit installed with your system provides control over all features of the CD Changer with the exception of the CD load and eject functions, which are controlled by buttons located on the front of the CD Changer. The radio also supplies the power, ground, PCI Bus, left and right speaker output thru a single DIN cable. All features you would expect, such as Disc Up/Down, Track Up/ Down, Random and Scan are controlled by the radio, which also displays all relevant CD Changer information on the radio display.

The CD Changer contains a Load/Eject button and an indicator light for each of the four disc positions. The individual light indicates whether a CD is currently loaded in that particular chamber of the CD Changer. Pressing the individual Load/Eject button for a particular chamber will eject a disc currently present in that chamber. If the chamber is currently empty, actuating the Load/Eject button will position that chamber to receive and load a new disc in that chamber.

BODY CONTROL MODULE
The body control module (BCM) supplies vehicle occupants with visual and audible information and controls various vehicle functions. To provide and receive information, the module is interfaced to the vehicle's serial bus communications network (PCI). This network consists of the powertrain control module (PCM), the transmission control module (TCM), the mechanical instrument cluster (MIC), the front control module (FCM), the occupant restraint controller (ORC), the compass/mini-trip (CMTC), the electronic vehicle information center (EVIC), the controller antilock brake (CAB), the HVAC control module (ATC & MTC), the power sliding door (Left & Right) modules (PSD), the power liftgate module (PLG), the Audio system, the side impact airbag control (left & right) modules (SIACM), the memory seat/mirror module (MSMM) and the sentry key immobilizer module (SKIM). The BCM is operational when battery power is supplied to the module.

The body control module provides the following features:
- Power Door Locks
- Automatic Door Lock
- Door Lock Inhibit
- Central Locking (with VTSS Only)
- Battery Protection
- The BCM will automatically turn OFF all exterior lamps after 3 minutes and all interior lamps after 15 minutes after the ignition is turned OFF, if they are not turned OFF by the driver.
- Chime Driver
- Compass/Minitrip Support
- Interior Lighting (Courtesy/Reading Lamps)
- BCM Diagnostic Reporting
- Electronic Liftgate Release (with Power Door Locks)
- Exterior Lighting
- Headlamp Time Delay (with/without Autoheadlamps)
- Automatic Headlamps (with electrochromatic mirror)
- Illuminated Entry
- Fade to OFF
- Headlamp Time Delay (with/without Autoheadlamps)
- Automatic Headlamps (with electrochromatic mirror)
- Illuminated Entry
- Fade to Off

This feature dims the interior lighting (courtesy lamps) gradually if the BCM does not receive any new inputs that would cause the interior lamps to remain ON.
- PWM Instrument Panel Dimming
- Door Lock Inhibit

This feature disables the door lock functions if the key is in the ignition and either front door is ajar. Pressing the RKE lock/unlock button under these conditions, result in normal lock/unlock activation.
- Power Sliding Door Switch Inputs

The BCM has 4 switch inputs for the power sliding door feature: Located in the overhead console are the Left and Right side sliding door switches to activate either or both sliding doors under the proper conditions. Also are B-Pillar switches located on the Left and Right B-pillar posts.
- Power Liftgate Switch Input

The BCM has 1 Liftgate switch input located in the overhead console
- Power Lockout Switch Input

The BCM has 1 Lockout switch that when enabled will disable the B-Pillar sliding door switches from activating either sliding door when depressed. When replacing a body control Module there are 2 modules available, a Base and a Midline. The Midline controller is used on vehicles that have Power Door Locks. If a vehicle is equipped with the Vehicle Theft Security System, the midline controller becomes a premium when the theft feature is enabled.

NOTE: DO NOT SWAP THE BODY CONTROL MODULE BETWEEN VEHICLES OR BODY CONTROL MODULES OFF THE SHELF.

Engineering does not recommend that service, dealers or the plant swap Body Control Modules (BCM) between vehicles or off the shelf. The BCM has internal diagnostic capability that assists in diagnosing the system. When an "Open" or a "Short" circuit exists, the diagnostic tool can be used to read the BCM codes. The codes are very descriptive in identifying the appropriate feature that has faulted.

CHIME WARNING SYSTEM
The BCM monitors the door liftgate ajar switches, multifunction switches, headlight switch, ignition switch, PCI bus, and the diagnostic tool to perform various chime operations. The BCM uses a low-side driver to control the chime located in the cluster.

The chime system provides the Driver with warning chimes for:
- Seat belt
- Exterior lights ON
- Key-in Ignition
- Key-in Accessory
- Engine temperature critical
- Low washer fluid
- Turn signals ON
- Dome light ON
- Low oil pressure
- Any warning lamp announcement
- High-speed warning (GCC)

The output sound intensity of the chime is approximately 72 decibels.

Chime Priority
The following list indicates the priority of the chime when more than one chime is active at the same time:
- Seat belt warning
- High-speed warning (GCC)
- Turn signal ON
- Chime request
- Warning lamp announcement

The cluster is responsible to set priority on all warning lamp announcement chimes.

Chime ON Conditions
The following is a list of the chime warnings and when they will sound.

Driver's Seat belt Unbuckled:
Sounds for approximately 6 ± 2 seconds when the ignition is turned ON and driver's seat belt is not buckled, as a reminder to the driver to buckle the seat belt.

Exterior Lights ON:
Ignition is in the lock position, the driver door is ajar, and the headlight switch is left in any position, other than auto or OFF. The chime will sound as a warning to the driver until one of the above conditions is removed or until the battery protection time of 3 minutes has expired.

Key-In Ignition:
Ignition is in the lock position, driver door is ajar and the key is in the ignition. The chime will sound until one of the above conditions is removed or until the battery protection time of 15 minutes has expired.

Turn Signal ON:
When the BCM detects a turn signal input continuously for 1.0 mile/ 0.6km and the vehicle speed is greater than 15 mph/24kph, the chime will sound until the specific turn signal is cancelled.

Dome Lights ON:
Ignition is in the lock position, driver doorajar, and the dome light switch is left in the ON position. The chime will sound until one of the above conditions is removed or until the battery protection time of 15 minutes has expired.

Low Oil Pressure:
The chime will sound when the engine is operating and the oil pressure drops below 4psi/27.5kPa.

Engine Temperature Critical:
The chime will sound when the engine is operating and the coolant temperature exceeds 252 °F/122C or 234 °/112C(diesel). The chime is continuous at 257 °F/125C and wilt chime for 4 minutes and stop if the temperature drops below 255 °F/123C.

Low Washer Fluid
The chime will sound when the washer fluid drops below a specific level.

Warning Lamp Announcement:
A chime will sound to alert the driver to scan the instrument panel to see which warning lamp is illuminated. The door/liftgate ajar warning lamp will appear without a chime if the vehicle is running and a door or the liftgate is opened. A chime will sound if the door or liftgate is still open and the vehicle speed is greater than 4mph/6kph.

High-speed warning (GCC)
The chime will sound, acting as a warning to the driver that the vehicle speed has exceed 75mph ± 2/120kph ± 3.

Warning Lamp Announcement
Low Fuel Lamp:
The cluster will request a single chime after the indicator is illuminated.

Volt Lamp:
The cluster will request a single chime after the indicator is illuminated.

Oil Pressure Lamp:
The cluster will request a single chime after illuminating the indicator above 450rpm vehicle operation.

Headlight Out Lamp:
The cluster will request a single chime after the indicator is illuminated.

Liftgate Ajar Lamp:
The BCM determines when to chime for liftgate ajar.

Fasten Seat Belt Lamp:
The BCM will request five chimes from the MIC when the ignition is turned to the unlock/run/start positions if the driver seat belt is not buckled.

Check Engine Lamp:
The cluster will request a single chime after the indicator is illuminated.

Low Washer Fluid Lamp:
The cluster will request a single chime after the indicator is illuminated.

Engine Temperature Lamp:
The cluster will request a single chime when the indicator is first illuminated at 252 °F/122C.

Other Chime ON Conditions
Bulb Check:
The chime will sound three times during bulb check.

Programming of Additional Key Fob:
A double cluster chime will sound, an which signals that the program mode has been initiated.

Programming for Rolling Door Locks:
When the programming has been completed, a single tone from the chime system, will occur.