Part 1 of 2
For additional information on the Base [1][2]CTM refer to Instrument Panel, Gauges and Warning Indicators / Audible Warning Device. Audible Warning DeviceSIX-STEP TROUBLESHOOTING PROCEDURE
Diagnosis 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 2000 Ram Truck consists of several modules that communicate over the CCD bus (Chrysler Collision Detection multiplex system). There are three additional modules, two types of Powertrain Control Modules (PCM) and the Controller Anti-Lock Brake (CAB) that are not part of the body system, but do utilize the CCD bus for communication. The CAB also utilizes the bus for diagnostics. The PCM sends and receives messages on the CCD bus, however diagnostics are performed through the Serial Communication Interface or SCI, the same as last year. All of the information about the functioning of all the systems is organized, controlled, and communicated by the CCD bus, which is described in (CCD Bus) 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 the 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
The Airbag Control Module (ACM) is secured to a bracket on the floor panel transmission tunnel below the instrument panel inside the vehicle. The ACM mounting bracket also serves as the instrument panel center support. The ACM contains a microprocessor, the impact sensor, and energy storage capacitor. The microprocessor contains the airbag system logic. The ACM system logic includes On-Board Diagnostics (OBD) capability, and communicates with the instrument cluster circuitry on the Chrysler Collision Detection (CCD) data bus to control the airbag indicator lamp.
The microprocessor in the ACM monitors the impact sensor signal and the airbag system electrical circuits to determine the system readiness. If the ACM detects a monitored system fault, it sends messages to the instrument cluster on the CCD data bus to turn on the airbag indicator lamp. A pre-programmed decision algorithm in the ACM microprocessor determines when the deceleration rate signaled by the impact sensor indicates an impact that is severe enough to require airbag system protection. When the programmed conditions are met, the ACM sends and electrical signal to deploy the airbag system components.
Only one impact sensor is used in this airbag system. The impact sensor is an accelerometer that senses the rate of the vehicle deceleration, which provides verification of the direction and severity of an impact. The impact sensor is calibrated for the specific vehicle, and is only serviced as a unit with the ACM.
The ACM also contains an energy-storage capacitor. This capacitor stores enough electrical energy to deploy the airbags, for one second following a battery disconnect or failure during and impact. The purpose of the capacitor is to provide airbag system protection in a severe secondary impact if the initial impact has damaged or disconnected the battery, but was not severe enough to deploy the airbags.
WARNING: THE AIRBAG SYSTEM IS A SENSITIVE, COMPLEX ELECTROMECHANICAL UNIT. BEFORE ATTEMPTING TO DIAGNOSE OR SERVICE ANY AIRBAG SYSTEM OR RELATED STEERING WHEEL, STEERING COLUMN, OR INSTRUMENT PANEL COMPONENTS YOU MUST FIRST DISCONNECT AND ISOLATE THE BATTERY NEGATIVE (GROUND) CABLE. THEN WAIT TWO MINUTES FOR THE SYSTEM CAPACITOR TO DISCHARGE BEFORE FURTHER SYSTEM SERVICE. THIS IS THE ONLY SURE WAY TO DISABLE THE AIRBAG SYSTEM. FAILURE TO DO THIS COULD RESULT IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSIBLE PERSONAL INJURY. NEVER STRIKE OR KICK THE AIRBAG CONTROL MODULE, AS IT CAN DAMAGE THE IMPACT SENSOR OR AFFECT ITS CALIBRATION. IF AN AIRBAG CONTROL MODULE IS ACCIDENTALLY DROPPED DURING SERVICE, THE MODULE MUST BE SCRAPPED AND REPLACED WITH A NEW UNIT.
The airbag warning lamp is the only point at which the customer can observe "symptoms" of a system malfunction. Whenever the ignition key is turned to the "run" or "start" position, the MIC performs a lamp check by turning the AIRBAG warning lamp ON for 6-8 seconds. If the lamp remains OFF it means that the ACM has checked the system and found it to be free of discernible malfunctions. If the lamp remains ON, there could be an active fault in the system or the MIC lamp circuit may be internally shorted to ground. If the lamp comes ON and stays ON for a period longer than 6-8 seconds then goes OFF, there is usually an intermittent problem in the system.
The MIC monitors the airbag warning lamp and seat belt warning lamp during the bulb check for a defective bulb or lamp driver circuit. The MIC tests the airbag lamp during the cluster bulb check and substitutes the seat belt lamp if the airbag lamp is defective. If the airbag lamp is defective the MIC will turn the seat belt light ON and OFF approximately 30 times to warn the driver that the airbag lamp is defective. The lamp status is sent to the ACM continuously via a CCD bus message. The seat belt lamp acts as a backup in the event that the AIRBAG lamp is defective. This information is sent to the ACM continuously via a CCD bus message.
Perform the WARNING LAMP BULB OR DRIVER procedure to find the cause of any customer complaint regarding the AIRBAG warning lamp, such as:
- warning lamp does not illuminate
- warning lamp stays illuminated with no active DTC's
The ACM cannot be repaired or adjusted and, if damaged or faulty, it must be replaced.
Driver Airbag Module (DAB)
The airbag protective trim cover is the most visible part of the driver side airbag system. The module is mounted directly to the steering wheel. Located under the trim cover are the horn switch, the airbag cushion, and the airbag cushion supporting components. The airbag module includes a housing to which the cushion and inflator are attached and sealed. The airbag module cannot be repaired, and must be replaced if deployed or in any way damaged. The inflator assembly is mounted to the back of the airbag module. The inflator seals the hole in the airbag cushion so it can discharge the gas it produces directly into the cushion when supplied with the proper electrical signal. The protective trim cover is fitted to the front of the airbag module and forms a decorative cover in the center of the steering wheel. Upon airbag deployment, this cover will split at a predetermined breakout line.
WARNING: THE AIRBAG MODULE INFLATOR ASSEMBLY CONTAINS SODIUM AND POTASSIUM NITRATE. THESE MATERIALS ARE POISONOUS AND EXTREMELY FLAMMABLE. CONTACT WITH ACID, WATER, OR HEAVY METALS MAY PRODUCE HARMFUL AND IRRITATING GASES (SODIUM HYDROXIDE IS FORMED IN THE PRESENCE OF MOISTURE) OR COMBUSTIBLE COMPOUNDS. IN ADDITION, THE PASSENGER AIRBAG MODULE CONTAINS ARGON GAS PRESSURIZED OVER 2500 PSI. DO NOT AT-TEMPT TO DISMANTLE AN AIRBAG MODULE OR TAMPER WITH ITS INFLATOR. DO NOT PUNCTURE, INCINERATE, OR BRING INTO CONTACT WITH ELECTRICITY. DO NOT STORE AT TEMPERATURE EXCEEDING 93 °C (200 °F).
Clockspring
The clockspring is mounted on the steering column behind the steering wheel. This assembly consists of a plastic housing which contains a flat, ribbon-like, electrically conductive tape that winds and unwinds with the steering wheel rotation. The clockspring is used to maintain a continuous electrical circuit between the instrument panel wire harness and the driver side airbag module, the horn switch, and the vehicle speed control switches on vehicles that are so equipped. The clockspring must be properly centered when it is installed on the steering column following any service removal, or it will be damaged.
The clockspring cannot be repaired it must be replaced.
Passenger Airbag Module (PAB)
The airbag door in the instrument panel top cover above the glove box is the most visible part of the passenger side airbag system. Located under the airbag door is the airbag cushion and it's supporting components. The airbag module includes a housing to which the cushion and inflator are attached and sealed. The airbag module includes a housing to which the cushion and inflator are attached and sealed. The airbag module cannot be repaired, and must be replaced if deployed or in any way damaged. The inflator assembly is mounted to the back of the airbag module. The inflator includes a small canister of highly compressed argon gas. The inflator seals the hole in the airbag cushion so it can discharge the compressed gas it contains directly into the cushion when supplied with the proper electrical signal. The airbag door has a living hinge at the top, which is secured to the instrument panel top cover. The door also has predetermined breakout lines concealed beneath its decorative cover. Upon airbag deployment, the airbag door will split at the breakout lines and the door will pivot out of the way.
The airbag module is secured at the bottom to the steel structural base of the instrument panel above the glove box opening. The airbag door is serviced as a unit with the passenger side airbag module, and includes the two passenger heating and air conditioning panel outlet housings. Following an airbag deployment, the airbag module and the instrument panel assembly must be replaced.
Passenger Airbag ON/OFF Switch
A passenger Airbag ON/OFF Switch located on the instrument panel allows the passenger airbag module to be turned off when certain child restraint devices are being used in the right front seating position. The switch is equipped with a key cylinder so that the switch position can only be changed using an ignition key. When the ignition switch is in the ON position and the passenger side airbag is OFF, a Light-Emitting Diode (LED) illuminates an "OFF" indicator lamp on the faceplate of the switch.
The passenger side airbag ON/OFF switch is located on the instrument panel. To turn OFF the passenger side airbag, turn the key actuator switch from the vertical position to a slanted position (pointing to the "OFF" light indicator), approximately 45 degrees clockwise. When the IGNITION is ON, this procedure will illuminate the "OFF" light indicator on the passenger airbag ON/OFF switch.
To re-enable the passenger side airbag, reverse the procedure above so that the key switch actuator is returned to a vertical position.
NOTE:
- Do not turn ignition ON with key in switch.
- Do not turn switch with ignition ON.
The Passenger Airbag ON/OFF Switch cannot be adjusted or repaired and, if faulty or damaged, the switch must be replaced.
WARNING: THE AIRBAG MODULE INFLATOR ASSEMBLY CONTAINS SODIUM AZIDE AND POTASSIUM NITRATE. THESE MATERIALS ARE POISONOUS AND EXTREMELY FLAMMABLE. CONTACT WITH ACID, WATER, OR HEAVY METALS MAY PRODUCE HARMFUL AND IRRITATING GASES (SODIUM HYDROXIDE IS FORMED IN THE PRESENCE OF MOISTURE) OR COMBUSTIBLE COMPOUNDS. IN ADDITION, THE PASSENGER AIRBAG MODULE CONTAINS ARGON GAS PRESSURIZED TO OVER 2500 PSI. DO NOT ATTEMPT TO DISMANTLE AN AIRBAG MODULE OR TAMPER WITH ITS INFLATOR. DO NOT PUNCTURE, INCINERATE, OR BRING INTO CONTACT WITH ELECTRICITY. DO NOT STORE AT TEMPERATURE EXCEEDING 93 °C (200 °F). 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.
Airbag 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.
Active diagnostic trouble codes for the airbag system are not permanent and will change the moment the reasoning 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-OFF, 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/function. 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 maximum of 12 seconds or as long as the malfunction is present.
The seat belt lamp replaces the airbag lamp if the airbag lamp is defective. The seat belt lamp pulses ON and OFF 30 times if the airbag warning lamp is defective.
Stored Codes
Airbag codes are automatically stored in the ACM'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 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 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 12 seconds, for example, 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, 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 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 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.
Airbag Trouble Codes
The airbag control module may report any of the following diagnostic trouble codes.
For the following codes, replace the airbag control module (ACM) even if set intermittently:
- ACM Accelerometer
- Firing Capacitor Low
- AECM Output Driver Circuit Open
- Logic Capacitor Low
- AECM Internal Diagnostic Code #1
- Safing Sensor Shorted
- Warning Lamp Driver Error
For these codes, refer to the appropriate diagnostic procedure:
Cluster Message Mismatch
Driver Squib Circuit Open
Driver Squib Circuit Shorted
Driver Squib Circuit Shorted to Battery
Driver Squib Circuit Shorted to Ground
Loss of Ignition Run Only
Loss of Ignition Run/Start
No Cluster CCD Message
Missing or Invalid VIN
Passenger Squib Circuit Open
Passenger Squib Circuit Shorted
Passenger Squib Circuit Shorted to Battery
Passenger Squib Circuit Shorted to Ground
VIN Mismatch
Warning Lamp Bulb or Driver
AUDIO SYSTEM
The factory-installed RAZ sales code radio receiver communicates on the Chrysler Collision Detection (CCD) data bus network through a separate two-way wire harness connector. This is used for the remote radio switches that are mounted to the steering wheel, and also used for radio diagnosis with the DRBIII.
The remote radio switches are resistor multiplexed units that are hard wired to the high line [1][2]CTM through the clockspring. The CTM monitors the status of the remote radio switches and sends the proper switch status messages on the Chrysler Collision Detection (CCD) data bus network to the radio receiver. The electronic circuitry within the radio is programmed to respond to these remote radio switch status messages by adjusting the radio settings as requested.
The Infinity speakers used in the premium speaker system are driven by dual amplifiers that are integral to each of the front door speakers. One of these dual amplifiers drives the front door speaker and the A-pillar mounted tweeter for that side of the vehicle, while the other amplifier drives the rear speaker for that side of the vehicle.
The filter, choke, and power relay unit is used to control the supply of fused battery current to the front door speaker-mounted dual amplifiers.
[1][2]CENTRAL TIMER MODULE
The Ram Truck utilize a Central Timer Module ([1][2]CTM). This system is available in a Base or High line configuration. The Base (IEM) configuration does not communicate on the CCD bus and will not be addressed. The CTM will handle most of the electronic timing and chime functions for the systems on the truck. The High line CTM provides the following features:
- Remote Keyless Entry (RKE)
- Central Locking Feature
- Chime
- Courtesy Lamp controls/Illuminated Entry
- Power Door Locks
- Speed Sensitive Intermittent Wipers
- Enhanced Accident Response
- Vehicle Theft Security System (VTSS)
The [1][2]CTM is located on the right side of the steering column behind the knee blocker on a metal bracket welded to the instrument panel. It contains a white 18-way and a green 14-way connector. For additional information on the Base CTM refer to Instrument Panel, Gauges and Warning Indicators / Audible Warning Device. Audible Warning Device
Chime System
The chime system is built into the [1][2]CTM. The system also supports an external chime request from the instrument cluster. This feature allows the instrument cluster to request a chime from the CTM for gauge problems and tell tale warnings. The CTM chime functions will have priority over the MIC chime requests. There are two chime rates, Low; 50 chimes per minute for reminders and High; 180 chimes per minute for serious conditions that require immediate attention. The high rate chime sounds when the key is left in the ignition and the driver doors is open or the headlights are left ON. The low rate chime sounds for any of the other conditions. There is a variable rate feature that allows the chime to sound continuously for key-in and headlamp warning as long as the door is open. The seat belt warning chime is activated for 4 to 6 seconds, and all other chime conditions will activate the chime once at the same time the warning light on the cluster is illuminated.
The chime will sound for the following conditions:
High Rate
- Key in Ignition Warning ignition OFF, key in ignition, drivers door open
- Ignition OFF, headlamps ON, drivers door open Low Rate
- Seat belt warning--6 seconds after key ON (6 to 8 chimes) or until belt is buckled
- Airbag lamp illuminated (3 times after prove-out)
- Anti-lock lamp illuminated (2 chimes after prove- out if equipped)
- Check engine lamp illuminated (2 chimes after prove-out)
- Check gauges lamp illuminated (2 chimes)
- Engine Temp High--when gauge enters red zone (2 chimes)
- Low fuel - when fuel level reaches 1/8 tank (2 chimes)
- Low washer fluid (2 chimes)
- Wait to start (diesel only) (2 chimes)
- Water in fuel (diesel only) ( 2 chimes)
If the ignition switch is turned to the run/start position and the driver's door is closed, then opened, the warning chime is defeated. This allows the doors to be open without the warning chime constantly sounding. The [1][2]CTM stays in this mode until the ignition switch is turned to the "OFF" position, then normal function will be restored. (Highline CTM only).
Enhanced Accident Response (Highline [1][2]CTM Only)
If the Airbag Control Module (ACM) deploys the airbags, a message is transmitted over the CCD bus to the CTM module to unlock the doors. The interior lights will be turned ON 10 seconds after getting zero speed message on the CCD bus.
In addition to unlocking the doors, the lock feature will be disabled for a predetermined amount of time following the deployment. Once the ignition key has been cycled to the "OFF" position, normal operation will resume. This is a programmable feature.