Part 3 of 3

LOW TIRE PRESSURE WARNING MODULE MODES
System Initialization
When the ignition is turned to the "run" position, the LTPW module performs a complete self-check of all electrical components in the system. After the vehicle reaches a speed of approximately 33 km/h (20 mph), the module will perform a dynamic check of the tire pressure transmitters. During the dynamic check, the vehicle speed may fall below 33 km/h (20 mph) but not for longer than one minute. The LTPW module will confirm if the Radio Frequency (RF) transmissions from each tire pressure transmitters have been received.

If any component exhibits a trouble condition during the initialization or dynamic check, the LTPW module will set a DTC and illuminate the "Low Tire" warning lamp. A fault can also occur if the LTPW module (after initialization) does not receive any transmissions from the transmitter/sensor for six consecutive ignition cycles.

Diagnostic Mode
Diagnostic mode is considered to be any time that the DRB is hooked up to the DLC and is communicating with the LTPW module. In diagnostic mode, the LTPW module does not monitor or accept the tire pressure sensor/transmitter signal. This means that you cannot read the tire pressure sensor/transmitter transmission information while driving the vehicle with the DRB hooked up.

Program Mode
The Program Mode enables the LTPW module to detect which wheel (LF, RF, RR, LR) is sending the signal. The module must learn each of the four tire pressure sensor/transmitters' identifications (ID). This transmitter ID "learning" is used so that if any other signals are being received by the LTPW module at this frequency, it won't be misinterpreted.

Programming is initially done at the assembly plant. If a LTPW module fails or one or more tire pressure sensor/ transmitter(s) fails, after replacement of the faulty component the LTPW module's diagnostic memory must be reprogrammed or cleared in order to relearn the transmitter ID.

The DRB can place the module in Program Mode. It is possible to reprogram only one tire pressure sensor/transmitter. To program a module place a magnet (special tool 8192) on the end of the LF wheel valve stem for approximately six seconds. The magnet will energize and close the Reed switch. With the Reed switch closed, the transmitter will transmit the identification (ID) and tire pressure to the module. After the module has learned that particular tire pressure sensor/ transmitter ID, the magnet should be moved to each of the other wheels in a clockwise direction. Hold the magnet at each wheel for six seconds before moving onto the next wheel. Exit the Program Mode. The module will store the locations of each transmitter ID. Using the DRB, verify that the module programming is complete by looking at the tire pressure sensor/transmitter ID's and pressure values.

MANUAL A/C (HVAC)/REAR WINDOW DEFOGGER
The Prowler comes standard with manual air-conditioning. The actuators for blend-air and fresh/recirc are cable operated. The mode door is electrically activated by the BCM based on input from the HVAC control head. The BCM uses an evaporator fin probe to prevent evaporator freeze-up.

When the ignition is in the "run" position, the body control (BCM) monitors the evaporator temperature state and the status of the A/C switch. Based on this information, the BCM sends a CCD message to the powertrain control module (PCM) indicating the A/C switch status and the evaporator temperature state.

The body control module controls the mode door position by receiving different voltage levels from the HVAC control over the HVAC mode sense circuit. Included in this signal is the input for the rear window defogger. The Rear Window Defogger button is located in the center of the Mode Control knob. Press this button once to turn on the Rear Window Defogger and a second time to turn it off. A LED in the button shows that the defogger is on. The defogger turns off automatically after 10 minutes of operation. Each later activation will allow 5 minutes of operation. The timer functions for the rear window defogger are controlled by the BCM.

POWER DOOR LOCKS
Power door locks are standard equipment on all Prowler vehicles and have the following features:
- Automatic door locks - automatically lock the doors when all doors are closed and the vehicle reaches a speed 18 mph. This feature can be enabled/disabled by the DRB Ill or by the customer cycling the ignition key from "Off to Run" four times (leaving the key in the off position) then pressing any power "lock" switch and removing the key from the ignition switch. A single chime will signal programming completed.
- Power door lock inhibit feature - cancels lock switch actuation when the key is in the ignition and either door is open.
- To prevent motor burnout, the BCM will pulse the lock/unlock relays a maximum of 4 seconds. Even though the switch may be held down longer.
- This vehicle is NOT equipped with central locking (unlocking one door with the key opens both doors). However, the vehicle is equipped with door key cylinder switches that are used exclusively for the vehicle theft security system and will arm or disarm the system.

Remote Keyless Entry (RKE) (Standard Equipment)
The body control module interfaces with the remote keyless entry receiver module via a one-way serial bus interface. The RKE module is located under the left side of the instrument panel top cover. It does not actuate relays directly but receives the signal from the transmitter and then communicates with the BCM.

Two transmitters are provided with each vehicle, but the RKE module is capable of accommodating four transmitters. The transmitters can be programmed by using the DRB III or the customer can add a transmitter providing a valid previously programmed transmitter exists. This is accomplished by pressing and holding the programmed transmitter unlock button from 4 to 10 seconds and then while still pressing the unlock button, press and release the panic button. This will put the BCM in programming mode. The customer will have approximately 30 seconds to Remote Keyless Entry (RKE) (standard equipment)

The body control module interfaces with the remote keyless entry receiver module via a one-way serial bus interface. The RKE module is located under the left side of the instrument panel top cover. It does not actuate relays directly but receives the signal from the transmitter and then communicates with the BCM.

Two transmitters are provided with each vehicle, but the RKE module is capable of accommodating four transmitters. The transmitters can be programmed by using the DRB III or the customer can add a transmitter providing a valid previously programmed transmitter exists. This is accomplished by pressing and holding the programmed transmitter unlock button from 4 to 10 seconds and then while still pressing the unlock button, press and release the panic button. This will put the BCM in programming mode. The customer will have approximately 30 seconds to press any button on each transmitter thereby programming that transmitter to the receiver. A technician with the DRB Ill can reprogram any RKE module providing VTSS is disarmed.

The RKE system, operated by the transmitter, has three modes of operation controlled by three buttons.
- Unlock button: Pressing the unlock button once will unlock the driver's door, disarm VTSS and illuminate the interior lamps. Pressing the unlock button twice within 5 seconds unlocks both doors.
- Lock button: Pressing the lock button locks all doors and sounds the horn once (if horn chirp is enabled).
- Panic button: When the panic button is pressed the horn is pulsed, the headlamps and marker lamps are flashed and the interior lamps are turned on. This will last for up to 3 minutes or until the panic button is pressed again or the ignition is turned on. The panic feature only works when the ignition is in the off position.

*Horn chirp: When all doors are closed and a lock command is sent by the RKE transmitter, a horn chirp will be heard. The horn chirp is also customer programmable by pressing and holding the lock button on the transmitter for 5 seconds and then while still holding the lock button, pressing the unlock button and releasing both. This will toggle (enable/disable) the horn chirp.

VEHICLE COMMUNICATION
The Chrysler Collision Detection multiplex system (CCD bus) consists of a twisted pair of wires. These wires run from one module to another. They receive and deliver coded information between the modules. The information is coded to identify the message as well as the importance of the message. When there are multiple messages trying to access the CCD bus at one time, the code determines the message that has higher priority, which is then allowed to access the bus first.

The two wires of the twisted pair that make up the CCD multiplex system are called "bus +" (bus plus) and "bus-" (bus minus) respectively. Each wire has a measurable voltage level of roughly 2.5 volts. In order to maintain the 2.5 volts on each line and provide a means of transportation for the coded messages, there is a "voltage divider network". This network consists of some modules with bias and some with termination. Bias is the part of the voltage divider network that places both bus + and bus - at 2.5 volts. Termination in the circuitry is required to complete the voltage divider network and also provides some electromagnetic protection for the bus.

NOTE: Communication over the bus is essential to the proper operation of the vehicle's on-board diagnostic systems and the DRB. Problems with the operation of the bus or DRB must be corrected before proceeding with diagnostic testing. If there is a problem, refer to the Vehicle Communications.

Bus Failure Messages
Short to Battery - Either or both of the bus wires are shorted to the battery potential.
Short to 5 Volts - Either or both of the bus wires are shorted to a 5-volt potential.
Short to Ground - Either or both of the bus wires are shorted to ground or a specific ground may be open.
Bus (+) & Bus (-) Shorted Together - The two bus wires are shorted together.
No Termination - The bus system has lost connection with all of its terminators.
Bus Bias Level Too Low - Either or both of the bus wire potentials are significantly below their normal 2.5 volts.
Bus Bias Level Too High - Either or both of the bus wire potentials are significantly above their normal 2.5 volts.
No Bus Bias - The bus system has lost connection with termination and/or bias.
Bus (+) Open - The bus (+) wire has lost connection with termination and/or bias.
Bus (-) Open - The bus (-) wire has lost connection with termination and/or bias.
Not Receiving Bus Messages Correctly - The DRB cannot communicate over the bus and does not know why.

VEHICLE THEFT SECURITY SYSTEM (VTSS)
The vehicle theft security system is controlled by the body control module and is standard equipment on all Prowler vehicles. It monitors the doors, decklid, hood and ignition circuit to determine if the alarm should be triggered and engine disabled. When the system is armed, the BCM removes the ground from the decklid release switch thereby preventing a thief from accessing the trunk area.

When the alarm is triggered, the engine becomes disabled. In addition the horn is pulsed, the headlamps and marker lights will flash for (3) three minutes. After the 3 minute alarm has expired the BCM will return to an armed state and ignore the input(s) that triggered the initial alarm, unless those inputs return to an inactive state. The VTSS LED will also flash at a new rate indicating that the vehicle has been tampered with. All other monitored inputs will re-trigger the (3) minute alarm if they become active.

If during the (3) minute alarming period the BCM receives a request from the RKE module to enter panic mode, the BCM will cancel the (3) minute alarm, return to VTSS armed state and then perform the RKE panic feature.

WIPER SYSTEM
The wiper system provides the driver with normal wipe (low and high speeds), intermittent wipe, wipe after wash, and pulse wipe functions. The driver selects the wiper function via a resistive multiplexed stalk switch mounted on the steering column. The low and high speeds are directly controlled via the multifunction switch. The intermittent function is controlled through the intermittent wiper relay and the BCM.

System Features
Speed Sensitive Intermittent Wipe Mode - There are 6 individual delay times with a minimum delay of � second to a maximum of 18 seconds. When the vehicle speed is under 10 mph, the delay time is doubled providing a range of 1 second to 36 seconds.

Pulse Wipe - When the wiper is in the off position and the driver presses the wash button for more than 62 milliseconds, but less than 1/2 second, 1 wipe cycle in low speed mode will be provided.

Wipe After Wash Mode - When the driver presses the wash button for over 1/2 second and then releases it, the wiper will continue to run for 2 additional wiper cycles.

The wiper system utilizes the BCM to provide intermittent operation. The low and high speed are run directly from the multifunction switch. The BCM controls the intermittent relay to change the wiper delay as the multifunction switch input changes. The BCM uses vehicle speed input to double the usual delay times below 10 mph.

DIAGNOSTIC TROUBLE CODE INFORMATION
Airbag Diagnostic Trouble Codes
For the following codes, replace the airbag control module (ACM).
- Internal Diagnostics 1
- Internal Diagnostics 2
- Internal Diagnostics 3
- Internal Diagnostics 4
- Low Stored Energy Driver
- Low Stored Energy Passenger
- Safing Sensor Shorted

For these codes, refer to the appropriate diagnostic procedure
- Driver Squib Circuit Open
- Driver Squib Circuit Shorted
- Front Sensor Circuit Open
- Loss of Ignition Run Only
- No CCD Bus Communication
- No Cluster CCD Bus Message
- One Front Sensor Circuit Open
- Passenger Squib Circuit Open
- Passenger Squib Circuit Shorted
- Pressure Switch Circuit Open/Shorted
- Safing Sensor Open
- Two Front Sensor Circuit Open
- Warning Lamp Circuit Open
- Warning Lamp Circuit Shorted

Body Control Module Diagnostic Trouble Codes
These require BCM replacement:
- EEPROM Checksum Failure
- INTERNAL ROM Test Failure

These BCM Codes are Diagnosable
- Battery Power to Module Disconnected
- SBEC Message Not Received
- EATX PRNDL Message Not Received
- Airbag Message Not Received
- Fuel Level Sending Unit Open or Shorted
- Left Door key Cylinder Switch Failure
- Right Door key Cylinder Switch Failure
- Door Lock Switch Failure
- Door Unlock Switch Failure
- A/C Mode Switch Mux Shorted to Battery
- A/C Mode Switch Mux Shorted to Ground
- HVAC Mode Door Selection Input Too High
- HVAC Mode Door Selection Input Too Low
- HVAC Mode Door Stalled
- Mode Door Motor Feedback Too High
- Mode Door Motor Feedback Too Low
- Rear Defogger Button Struck Tire Pressure Module Input Circuit Fault
- Tire Pressure System Fault
- Volume up Switch Failure (Stuck)
- Volume down Switch Failure (Stuck)
- Seek up Switch Failure (Stuck)
- Seek down Switch Failure (Stuck)
- Preset Switch Failure (Stuck)
- PAB On/Off Switch Mux Circuit Open/Shorted

CCD Radio Diagnostic Trouble Codes
- Main Micro
- Radio Error
- Shorted Front Channel
- Shorted Rear Channel

Low Tire Pressure Codes
- Left Front Low Tire Pressure
- Left Rear Low Tire Pressure
- Right Front Low Tire Pressure
- Right Rear Low Tire Pressure
- Left Front Tire Pressure Transmitter Low Battery
- Left Rear Tire Pressure Transmitter Low Battery
- Right Front Tire Pressure Transmitter Low Battery
- Right Rear Tire Pressure Transmitter Low Battery
- LTPW Module/Left Front Tire Pressure Transmitter Failure
- LTPW Module/Left Rear Tire Pressure Transmitter Failure
- LTPW Module/Right Front Tire Pressure Transmitter Failure
- LTPW Module/Right Rear Tire Pressure Transmitter Failure

DRB III ERROR MESSAGE
Under normal operation, the DRB will display one of only two error messages:
- User-Requested WARM Boot or User-Requested COLD Boot

If the DRB should display any other error message, record the entire display and call the MDS Hotline, or call for information and assistance at 1-800-825-8737. This is a sample of such an error message display:

ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548 err: Oxi
User-Requested COLD boot

Press more to switch between this display and the application screen.
Press F4 when done noting information

DRB III DOES NOT POWER UP (BLANK SCREEN)
If the LED's do not light or no sound is emitted at start up, check for loose cable connections or a bad cable. Check the vehicle battery voltage (data link connector cavity 16). A minimum of 11 volts is required to adequately power the DRB.

If all connections are proper between the DRB and the vehicle or other devices, and the vehicle battery is fully charged, an inoperative DRB may be the result of faulty cable or vehicle wiring. Perform VEHICLE COMMUNICATION TEST 1A.

DRB Scan Tool:

DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the display. Adjust the contrast to compensate for this condition.

VEHICLE PREPARATION FOR TESTING
Make sure the vehicle being tested has a fully charged battery. If it does not, false diagnostic codes or error messages may occur.

SERVICING SUB-ASSEMBLIES
Some components of the body system are intended to be serviced as an assembly only. Attempting to remove or repair certain system sub-components may result in personal injury and/or improper system operation. Only those components with approved repair and installation procedures should be serviced.

DRB III SAFETY INFORMATION

WARNING: Exceeding the limits of the DRB multimeter is dangerous. It can expose you to serious or possibly fatal injury. Carefully read and understand the cautions and the specification limits

- Follow the vehicle manufacturer's service specifications at all times.
- Do not use the DRB if it has been damaged.
- Do not use the test leads if the insulation is damaged or if metal is exposed.
- To avoid electrical shock, do not touch the test leads, tips, or the circuit being tested.
- Choose the proper range and function for the measurement. Do not try voltage or current measurements that may exceed the rated capacity.
- Do not exceed the limits shown in the table below:

FUNCTION - INPUT LIMIT
Volts - 0 - 500 peak volts AC, 0 - 500 volts DC
Ohms (resistance)* - 0-1.12 megohms
Frequency Measured, Frequency Generated - 0-10kHz
Temperature - -58 - 1100° F, -50 - 600° C

* Ohms cannot be measured if voltage is present. Ohms can be measured only in a non-powered circuit.

- Voltage between any terminal and ground must not exceed 500v DC or 500v peak AC.
- Use caution when measuring voltage above 25 V DC or 25 V AC.
- The circuit being tested must be protected by a 10A fuse or circuit breaker.
- Use the low current shunt to measure circuits up to 10A. Use the high current clamp to measure circuits exceeding 10A.
- When testing for the presence of voltage or current, make sure the meter is functioning correctly. Take a reading of a known voltage or current before accepting a zero reading.
- Use caution when measuring voltage above 25 V DC or 25 V AC.
- The circuit being tested must be protected by a 10A fuse or circuit breaker.
- Use the low current shunt to measure circuits up to 10A. Use the high current clamp to measure circuits exceeding 10A.
- When testing for the presence of voltage or current, make sure the meter is functioning correctly. Take a reading of a known voltage or current before accepting a zero reading.

WARNINGS
Vehicle Damage Warnings
Before disconnecting any control module, make sure the ignition is "off". Failure to do so could damage the module.

When testing voltage or continuity at any control module, use the terminal side (not the wire end) of the connector. Do not probe a wire through the insulation; this will damage it and eventually cause it to fail because of corrosion.

Be careful when performing electrical tests so as to prevent accidental shorting of terminals. Such mistakes can damage fuses or components. Also, a second code could be set, making diagnosis of the original problem more difficult.

Road Testing A Complaint Vehicle
Some complaints will require a test drive as part of the repair verification procedure. The purpose of the test drive is to try to duplicate the diagnostic code or symptom condition.

CAUTION: Before road testing a vehicle, be sure that all components are reassembled. During the test drive, do not try to read the DRB screen while in motion. Do not hang the DRB from the rear view mirror or operate it yourself. Have an assistant available to operate the DRB.