Part 1 of 3
SIX-STEP TROUBLESHOOTING PROCEDUREDiagnosis of the body system is done in six basic steps:
- verification of complaint
- verification of any related symptoms
- symptom analysis
- problem isolation
- repair of isolated problem
- verification of proper operation
SYSTEM DESCRIPTION AND FUNCTIONAL OPERATION
The body system on the Prowler consists of a combination of modules that communicate over the CCD bus (Chrysler Collision Detection multiplex system). All of the information about the functioning of all the systems is organized, controlled, and communicated by the CCD bus, which is described in Vehicle Communication of this general information.
Through the CCD bus, information about the operation of vehicle components and circuits is relayed quickly to the appropriate module(s). All modules receive all the information transmitted on the bus even though a module may not require all information to perform it's function. It will only respond to messages "addressed" to it through a binary coding process. This method of data transmission significantly reduces the complexity of the wiring in the vehicle and the size of wiring harnesses.
AIRBAG SYSTEM
Functional Operation
The airbag system was designed to provide increased driver and passenger protection if the vehicle is involved in a front-end collision. The system was designed to be, and is most effective when used in conjunction with the seat belt system. The passenger side airbag assembly utilizes a canister of compressed, inert gas to inflate the bag. This gas is expanded at a very high rate through a heating process, that allows a small quantity of gas under a very high pressure to inflate the large passenger airbag.
The Prowler utilizes two front impact sensors, located on each side of the battery and a safing sensor located in the ACM to control the deployment of the airbags. Diagnosis of the system is done through the Data Link Connector (DLC) located under and just to the left of the steering column.
The airbag lamp is located in the cluster. Whenever the ignition key is turned to the "run" position, the cluster illuminates the bulb for 7 seconds. This illumination is called bulb prove-out. After the 7 seconds, the bulb will normally extinguish. The bulb will illuminate if the ACM senses a fault in the Airbag system and communicates this message to the cluster via the CCD bus. The cluster will also light the light if the ACM fails to communicate with it for 5 consecutive seconds. If for some reason the cluster illuminates the airbag lamp, it will keep the lamp illuminated for a minimum of 12 seconds. This lamp is not dimmable.
The ACM monitors critical input and output circuits within the airbag system, making sure they are operating correctly. Some circuits are tested continuously; others are checked only under certain circumstances. The ACM provides diagnostic information about the airbag system to the technician through the DRBIII(R) via the CCD bus.
The deceleration or g-force resulting from the impact of a front-end collision causes the front sensors to close. The safing sensor is designed to close from much lower g-forces than the front sensors. As soon as one of the front impact sensors and the safing sensor are closed, an electrical charge is sent to the airbag module. This causes the inflator to be actuated, thus deploying the airbags. The total time from the closure of the sensors to deployment and deflation of the airbags is less than 1/10 of one second.
The ACM also contains an energy storage capacitor. This capacitor stores enough electrical energy to deploy the airbags for up to two minutes following a battery disconnect or failure. The purpose of the capacitor is to provide airbag deployment in a severe secondary impact if the initial impact has damaged or disconnected the battery; but was not severe enough to deploy the airbags. The AIRBAG warning lamp is the only point at which "symptoms" of a system malfunction can be observed by the customer.
REPLACE AIRBAG SYSTEM COMPONENTS ONLY WITH PARTS SPECIFIED IN THE CHRYSLER MOPAR PARTS CATALOG. SUBSTITUTE PARTS MAY APPEAR INTERCHANGEABLE, BUT INTERNAL DIFFERENCES MAY RESULT IN INFERIOR OCCUPANT PROTECTION. THE FASTENERS, SCREWS, AND BOLTS ORIGINALLY USED FOR THE AIRBAG SYSTEM COMPONENTS HAVE SPECIAL COATINGS AND ARE SPECIFICALLY DESIGNED FOR THE AIRBAG SYSTEM. THEY MUST NEVER BE REPLACED WITH ANY SUBSTITUTES. ANY TIME A NEW FASTENER IS NEEDED, REPLACE IT WITH THE CORRECT FASTENERS PROVIDED IN THE SERVICE PACKAGE OR SPECIFIED IN THE CHRYSLER MOPAR PARTS CATALOG.
Passenger Airbag ON/OFF Switch
The passenger side airbag ON/OFF switch is located on the right end cap of the instrument panel. To de-activate the passenger side airbag, insert the ignition key, turn the key actuator switch from the ON position to the OFF position, approximately 45 degrees clockwise from the "ON" position, remove the key completely from the switch and verify that the switch actuator hole stays in the new position. The switch is spring loaded and will return to the "ON" position unless you remove the key. The switch cannot be adjusted or repaired, if faulty or damaged the PAB ON/OFF switch must be replaced.
To re-enable the passenger airbag, reverse the procedure above so that the ON/OFF key switch actuator is returned to a ON position.
NOTE: DO NOT TURN IGNITION ON WITH KEY IN SWITCH. DO NOT CHANGE SWITCH POSITIONS WITH IGNITION ON. DO NOT LEAVE THE KEY IN THE SWITCH UNDER ANY CONDITION.
The PAB ON/OFF switch is a resistive multiplexed signal to the BCM. The BCM will monitor the input from the ON/OFF switch every 31.25 ms, regardless of the ignition status, calculating an average voltage created by the resistive switch (old reading + new reading/2). Every 250 ms the BCM will read the average voltage value created by the switch and determine the appropriate switch state. The BCM will monitor the ON/OFF switch for four states. Two for diagnostic purposes and the remaining two for switch positions, ON or OFF. A DTC will be stored in the BCM if the average voltage level should indicate that a ON/OFF switch is shorted to ground or open circuit, and this condition last for more than 10 seconds. The ON/OFF warning lamp is located in the instrument cluster and will be illuminated when the switch is in the OFF position. When a DTC is active the warning lamp will be flashed ON and OFF at a rate of 0.25 Hz (2 seconds ON and 2 seconds OFF). If the condition is corrected the warning lamp will be turned OFF within 250ms and the DTC will be erased after 20 ignition cycles. The BCM will perform a 6 second bulb check when the ignition is turned ON. The bulb test will be shortened if the vehicle is in gear and the road speed is above 5 mph.
Active Codes
An active trouble code indicates an on-going malfunction. This means the defect is there every time the ACM checks that circuit/function. It is impossible to erase an active code; active codes are automatically erased by the ACM when the reason for the code has been corrected.
Stored Codes
Airbag codes are continuously stored in the ACM's memory when the ignition is turned OFF with the exception of 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 active code could be.
When a trouble code occurs, the AIRBAG warning lamp 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 that 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 that was present for two minutes 13 seconds would be three minutes.
If a malfunction is detected, a diagnostic trouble code is stored and will remain stored as long as the malfunction exists. When and if the malfunction ceases to exist the code is stored and an ignition cycle count will be initiated for the code. If the ignition cycle count reaches 100 without reoccurrence of that same malfunction, that 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 the 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 the stored code, 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
There is one audio system available on Prowler. It consists of a corporate RBN radio with a 5 band equalizer and an external six disc CD changer mounted behind the passenger seat back. The system also incorporates an amplifier located under the passenger seat. The amplifier drives all the speakers. The speaker locations are: one in each corner of the instrument panel and one in each door. The rear speaker enclosure which is mounted behind the seats contains 2 - 3.5 inch full range speakers, one on each side of the rear speaker enclosure, and one centrally mounted dual coil subwoofer.
The speaker enclosure is made of a very thick roto-cast plastic. The enclosure is a two-piece design, it is the housing for a 6.5 inch dual voice coil sub-woofer and 2 - 3.5 inch full range speakers. The dual coil feature allows one speaker to handle the left and right channels of a stereo signal. The sub-woofer handles frequencies from approximately 60 to 80 hertz. It is electronically crossed over by circuitry in the amplifier and also acoustically by the design of the enclosure. The subwoofer is located in a ducted port style of enclosure. The subwoofer is mounted and sealed into the back part of the enclosure while, the front of the speaker cone works into a ducted port that effectively extends the low range of the speaker and also increases the efficiency of the system. When completely assembled, the subwoofer is not visible from the outside of the housing. All of the bass from the woofer exits through the ducted port located at approximately the passengers left shoulder area. Bass is characteristically non-directional so the physical location of the port is not critical for good bass reproduction. The housing assembly with speakers weighs approximately 14 pounds.
The amplifier, located under the passenger seat, is an 8 x 40 system. That is, 8 channels at 40 watts each for a total of 320 watts. It is built by Infinity/Harman audio system. It is turned ON with an ON/OFF signal from the radio and is responsible for driving all speakers and handling the cross over internally. Internal electronic crossovers allow more efficient splitting of the frequencies without losses associated with passive crossover systems. The amplifier also has short circuit protection in case of a speaker failure.
The audio system is equipped with an auto volume control feature which allows for automatic audio volume adjustment to compensate for road and wind noise at vehicle speeds above 20 mph (33 km/h). The auto volume switch is hard wired to the body control module. The body control module provides a CCD Bus message to the radio indicating one of the following switch positions:
OFF - no volume change with speed change.
LOW - moderate volume change with speed, designed to adjust volume to road/wind noise levels with the convertible top up and windows closed.
HIGH - aggressive volume change with speed, designed to adjust volume to road/wind noise levels with the convertible top down and windows open.
There are remote control switches on the back of the steering wheel for volume up/down, seek up, seek down, and preset station selections. For this reason, the radio will be connected to the CCD bus and will allow some diagnostics of the system with the DRBIII(R).
The antenna is sandwiched between two layers of the windshield. To provide better range, it uses an amplifier that is located under the I/P top cover on the passenger side. The antenna amplifier is turned ON with the ON/OFF signal from the radio.
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 (the Chrysler Collision Detection bus, or CCD bus). This network consists of the powertrain control module (PCM), the transmission control module (TCM), the electro/mechanical instrument cluster (MIC), Compass Mini-Trip Computer (CMTC), the radio (RBN) and the airbag control module (ACM). The BCM is operational when battery power is supplied to the module. Ignition switch power is needed for ignition switch functions.
The Body Control Module provides the following features:
Interior Lighting
Inside Mirror/Reading Lamps
Ignition Key Halo Lamp
Illuminated Entry
Battery Protection (load shedding)
Windshield Wipers/Washers
Intermittent Wipe, Speed Sensitive Wipe and Wipe after wash
Instrument Cluster Support
Gauge positioning and CCD Lamp Drive
Instrument Cluster Dimming
Vehicle Theft Security System (VTSS)
Door Locks
Power
Auto Door Locks
Remote Keyless Entry (RKE)
Door Lock Inhibit
Exterior Lamp Control
Controls Parklamps, Low & High Beam
Headlamps
Headlamp Time Delay
Remote Radio Controls
Auto Volume Radio Control
Chime
Climate Control Support
Low Tire Pressure Warning interface for operation of LTPW Lamp
Body Control Module Systems Supported
The BCM receives information over the CCD Bus from the PCM in order to support certain features.
The required information is a follows:
- Engine RPM
- Injector ON Time and Distance Pulses
- Vehicle Speed
- Engine and Battery Temperature
- Charging System Failure, Engine Temperature Limp-In, VTSS Arming Status
- Engine Model
- "Service Engine Soon" Lamp Status
The BCM provides the PCM with information on the A/C switch status and the "OK to Start" or VTSS status.
Compass Mini-trip Computer
The Compass Mini-Trip Computer (CMTC) is integrated into the rear view mirror. The CMTC receives CCD Bus messages which contain some of the information necessary to provide the driver with direction of vehicle travel, current outside temperature, as well as the following traveler navigational information: average fuel economy, distance to empty, instant fuel economy, elapsed time and trip odometer. This information is available in standard or metric form where applicable.
CHIME SYSTEMS
The Chime System is an integral part of the Body Control Module (BCM) and provides the driver with two types of chimes, Warning and Announcement. The BCM monitors its hardwired inputs and CCD bus messages to determine when a chime is needed. The Warning Chimes are a dual tone chime for the following conditions: Seat Belt Unbuckled, Exterior Lamps ON, Key-In Ignition, Critical tire pressure, and Dome Lamps ON. The Announcement Chime is a single tone chime to warn the driver when an instrument cluster gauge is out of range or a warning lamp is ON. Refer to the General Information System Description and Functional Operation for more information on the Instrument Cluster gauges and warning lamps.
During shipment (with the IOD fuse disconnected) the Warning and Announcement chimes will not work with the ignition key turned OFF.
Warning Chimes
Seat Belt Chime
The seat belt chime will sound for up to 8 seconds, when the ignition is turned ON and the driver's seat belt is unbuckled, as a reminder to the driver to buckle the seat belt. Buckling the driver's seat belt before the time out has expired will cause the chime to stop immediately. The seat belt lamp will stay ON for 7 seconds even if the seat belt is buckled or stay ON as long as the ignition key is ON if the seat belt remains unbuckled.
Exterior Lamps ON Chime
The Exterior Lamp ON Chime will act as a warning to the driver that the exterior lights have been left ON. If the ignition is OFF, the driver's door is open, and the park lamps or headlamps are ON, the chime will sound until one of the conditions is removed or until the battery protection timeout of 3 minutes.
Key-in Ignition Chime
The key-in Ignition Chime will act as a warning to the driver that the key has been left in the ignition. If the ignition is OFF and not in the accessory power position, the driver's door is open or ajar, and the key is in the ignition, the chime will sound until one of the conditions is removed or the battery protection timeout of 15 minutes has expired.
Courtesy Lamp ON Chime
The Courtesy Lamp ON Chime will act as a warning to the driver that the dome lamps have been left ON. When the ignition is OFF, driver's door is open, and the dome lamps are ON, the chime will sound continuously until one of the conditions is removed or until the battery protection timeout of 15 minutes has expired.
Turn Signal ON Chime
The Turn Signal ON Chime will act as a warning to the driver that the turn signals have been left ON. When a level change is detected on the turn signal inputs to the BCM continuously for approximately 1 mile, and the vehicle speed is greater than 15 MPH, the chime will sound continuously until the turn signal inputs are no longer active. If vehicle speed drops below 15 MPH prior to the warning being activated the accumulated distance traveled will be reset. Chime rate is approximately 50 chimes per minute.
Airbag Warning Lamp Announcement Chime
The Airbag Warning Lamp is monitored by the BCM. If the engine exceeds 450 RPM for more than 10 seconds and the airbag warning lamp is ON, a single chime will be sounded. The chime will not be rearmed until the vehicle speed equals zero and the Airbag Warning Lamp is OFF.
Warning Lamp Announcement Chime
The Warning Lamp Announcement Chime will act as a warning to the driver to scan the instrument cluster to observe which lamp is illuminated. Whenever the check gauges, low fuel, low washer level, service engine soon, system voltage failure, or low tire pressure lamps are first illuminated, the chime will sound for one tone. If a door or the decklid is ajar, the chime will continue to sound until the item ajar is closed or the ignition is switched OFF.
The low tire pressure critical chime will sound with each flash of the low tire warning lamp.
During the first two seconds of the ignition ON or until the seat belt warning chime ends, all announcement chimes will be consolidated into one warning announcement. This will occur two seconds after the seat belt warning chime ends. If a warning announcement should occur while a higher priority warning chime is in process, no additional warning lamp announcement chime will be given after the chime in process ends. All associated lamps will illuminate and the active chime will serve as the warning announcement.
In the case of the chime warning associated with the Service Engine Soon lamp, the chime will sound only the first illumination of this lamp. Any other condition that could normally activate the warning announcement associated with the service engine soon lamp will not reactivate the chime if the lamp is currently illuminated.
NOTE: IF THE CCD BUS COMMUNICATION WITH THE ENGINE CONTROLLER IS LOST, THE BCM ASSUMES A VEHICLE SPEED OF 3 MPH. THIS RESULTS IN THE DOOR AJAR WARNING TONE BEING SOUNDED IMMEDIATELY WHENEVER A DOOR BECOMES AJAR.