Part 2 of 2
AUDIO SYSTEMThere are six radio systems available that will be on the PCI Bus. They are the RBB, RAZ, RBK (late introduction), RAD, RBY and RBT. The RBB, RAZ and RBK are for the US market and the RAD, RBY and RBT are for export or BUX. Each radio system comes equipped with a standard premium 6 speaker system. The speakers are located in the instrument panel, the front doors and the rear pillars. The instrument panel speakers are a tweeter type speaker for high frequency. The front door speakers are a woofer/midrange type speaker. The rear "D" pillar speakers are a full range type speaker. Depending on the manufacture, some systems will have a Front/Rear channel system and others will have a Left/Right channel system. If one of the speaker circuits experiences a short, the other speakers on that channel will also shut down until the circuit is repaired. The radio will also set a trouble code, which the DRB III can display, indicating which channel is effected.
INSTRUMENT CLUSTER
The instrument cluster for the PT body is referred to as an "Electro-Mechanical Instrument Cluster" (EMIC). Some of the features are that it controls all the gauges, the courtesy lamps, it receives and sends messages to other modules via the PCI bus circuit, it controls all the instrument illumination and the chime is also an integral part of the cluster. The front turn signals are wired through the cluster and then go to the front lamps. The reason being that the DRL module is built into the cluster if the cluster is so equipped.
One button is used to switch the display from trip to total mileage. Holding the button when the display is in the trip mode will reset the trip mileage. This button is also used to put the cluster in self diagnostic mode. To put in self diagnostic mode, press the button down and turn the ignition to the run position. The gauges will increment to selected stops and all bus operated indicators will light. All indicators are LED's and are not replaceable, with the exception of the high beam indicator which is a bulb. The gauges are also not individually replaceable thereby requiring complete replacement of the cluster if one LED indicator or gauge is defective. The oil lamp will come on when the ignition is turned ON and the engine is OFF, and most of the indicators will also come ON briefly for a bulb check when the ignition is turned from OFF to run. All of the gauges (except Fuel Gauge) receive their information via the PCI bus from the power train control module.
The seat belt indicator will stay ON continuosly unless the seat belt is buckled. The chime will sound for 6 seconds if the belt is unbuckled when the ignition is first turned ON.
In the event that the instrument cluster looses communication with other modules on the PCI bus, the cluster will display "no bus" in the VF display The VF display also displays "Door", "Cruise", "Trac" and odometer trip or total.
If the cluster does not detect voltage from the battery circuit, the message "FUSE" will alternate with the odometer/trip odometer after the ignition is turned ON and will continue until the vehicle is first moved. The lack of voltage can be due to the M1 Fused B(+) (IOD) fuse being open or a circuit problem.
REMOTE KEYLESS ENTRY MODULE
The Remote Keyless Entry module controls the Power Door Locks and the Vehicle Theft Security System (VTSS). It also wakes up the Instrument Cluster to turn ON the illuminated entry when it senses a signal from the RKE transmitter. The module communicates with other modules via the PCI bus circuit.
The RKE module monitors the Occupant Restraint Controller messages for the purpose of monitoring the deployment of the airbag. Upon receiving that message along with the verification that the ignition is ON and the vehicle speed is zero, it will provide the "enhanced accident response feature". This feature will cause the module to unlock all doors and the instrument cluster to turn the courtesy lamps ON.
The RKE module communicates with the Powertrain Control Module to receive vehicle speed information to activate the rolling door lock feature, receive the "okay to lock" message, to receive the vehicle information number and receive body style information. Two transmitters are supplied with the vehicle but a total of 4 can be programmed to the module. The horn chirp on vehicle lock command is customer programmable.
To limit the amount of battery drain during storage, the module has 3 modes of operation: ship mode, dealer storage mode and customer usage mode. To change from ship mode to dealer storage mode, the DRB III may be used or the ignition switch cycled up to 30 times. To transfer from dealer storage to customer mode, install the IOD fuse and cycle the ignition switch. To transfer back to dealer storage mode, the DRB III must be used, the IOD fuse removed, and the ignition switch cycled. Sometimes the instrument cluster doesn't transmit a message upon change of the IOD fuse. By cycling the ignition, this causes the cluster to transmit the message, thereby ensuring the RKE module has received the most recent IOD status.
Vehicle Theft Security System
The VTSS monitors the vehicle doors, liftgate, hood and the ignition for unauthorized operation. The alarm activates by sounding the horn, flashing the headlamps, park lamps and the VTSS indicator in the instrument cluster. Locking the doors with the door lock switch (through following a normal exit sequence of opening the door, pressing the lock button, and closing the door), the door cylinder lock switches or the RKE transmitter arms the system. During the 16 second arming process the VTSS indicator will flash quickly and when the system is armed will slow down. If the hood switch is grounded the LED will stay ON steady during arming. The engine kill feature is accomplished via the Sentry Key Immobilizer Module (SKIM).
All of the sensors for the VTSS system can be monitored using the DRB III. The DRB III is also useful to determine the cause of a customer complaint of the alarm going OFF with no apparent reason.
Panic Mode
Upon activation of the panic function the head lamps and park lamps flash in an alternating manner, the horn pulses every second and the courtesy lamps are turned ON. The panic mode allows normal night time driving by allowing the headlamps and park lamps to be ON steady when the headlamp switch is in the ON position. Panic mode is activated immediately by pressing the panic button once. It does not disarm the VTSS or unlock the doors. It is canceled by pressing the button a second time, reaching a vehicle speed greater than 15 mph or after 3 minutes has elapsed in panic mode. Once panic mode has been activated there is a 2-second delay before it will turn OFF. Once it is cancelled there is a 2-second delay before it can be reactivated. This is to avoid the problem of deactivating and immediate reactivating due to multiple button presses.
POWER DOOR LOCKS
Central Locking
This feature allows the customer to lock/unlock all vehicle doors with the key from either front door or liftgate lock cylinder switch. The customer can choose to program this feature to unlock all doors with one turn of the key or open the driver door only with the first turn of the key and open the other doors with the second turn. Altering the operation of the unlock function via the key cylinder switch from one turn to two turns will also alter the operation of the RKE transmitter from one press to two presses.
Rolling (automatic) Door Locks
All vehicle door (including liftgate) are locked automatically once the vehicle reaches a speed of 15 mph and all doors (excluding liftgate) are closed. This feature can also be enabled/disabled by the customer.
Door Lock Inhibit
This feature disables the door lock command from the interior door lock switch whenever the driver door is open and the key is in the ignition. This prevents the driver from locking the keys in the ignition when using the power door locks. This feature is inoperable if the IOD fuse is not installed.
SENTRY KEY IMMOBILIZER SYSTEM (SKIS)
The SKIS is an immobilizer system designed to prevent unauthorized vehicle operation. The system consists of a Sentry Key Immobilizer Module (SKIM) and ignition key(s) called Sentry Key(s) which are equipped with a transponder chip. The SKIM communicates over the Programmable Communication Interface multiplex system (PCI) bus network to the instrument cluster, Powertrain Control Module (PCM), and the DRB III scan tool.
The SKIM sends messages to the instrument cluster over the PCI bus to control the VTSS indicator lamp. The SKIM sends a message to the instrument cluster to turn the lamp ON for about three seconds when the ignition is turned to the RUN/START position as a bulb test. If the indicator lamp comes ON and stays ON after the bulb test, it indicates that the SKIM has detected a system malfunction and/or that the SKIS has become inoperative. If an invalid key is detected in the ignition key cylinder with the ignition switch in the RUN/START position the SKIM will flash the VTSS indicator lamp ON and OFF.
For additional information on the SKIS, refer to the Powertrain Diagnostic Procedures.
COMMUNICATION
The Programmable Communication Interface or DRB III Bus is a single wire multiplexed network capable of supporting binary encoded messages shared between multiple modules. The PCI bus circuit is identified as D25 and is violet with a yellow tracer. The modules are wired in parallel. Connections are made in the harness using splices. The following modules are used on 2001 PT:
- Occupant Restraint Controller
- Left SIACM
- Right SIACM
- Controller Antilock Brake
- Powertrain Control Module
- Remote Keyless Entry Module
- Sentry Key Immobilizer Module
- Radio
- Transmission Control Module
- Mechanical Instrument Cluster
Each module provides its own drive and termination in order to transmit and receive messages. The bus voltage is at zero volts when no modules are transmitting and is pulled up to about seven and a half volts when modules are transmitting.
The bus messages are transmitted at a rate averaging 10.4k bits per second. Since there is only voltage present when the modules transmit and the message length is only about 500 milliseconds, it is ineffective to try and measure the bus activity with a conventional voltmeter. The preferred method is to use DRB III lab scope. The 12 V square wave selection on the 20-volt scale provides a good view of the bus activity. Voltage on the bus should pulse between zero and about seven and a half volts. Refer to the figure for some typical displays.
The PCI Bus failure modes are broken down into two categories. PCI Bus Communication Failure and individual module no response. Causes of a PCI Bus Communication Failure include a short to ground or battery on the PCI circuit. Individual module no response can be caused by an open circuit at the module, or an open battery or ground circuit to the affected module.
Symptoms of a PCI Bus Communication Failure would include but are not limited to:
- All gauges on the MIC stay at zero
- All telltales on MIC illuminate
- MIC backlighting at full intensity
- No response received from any module on the PCI bus
- No start (if equipped with Sentry Key Immobilizer)
Symptoms of individual module failure could include any one or more of the above. The difference would be that at least one or more modules would respond to the DRB III.
Diagnosis starts with symptom identification. If a PCI Bus Communication Failure is suspected, begin by identifying which modules the vehicle is equipped with and then attempt to get a response from the modules with the DRB III. If any modules are responding, the failure is not related to the total bus, but can be caused by one or more modules PCI circuit or power supply and ground circuits. The DRB III may display "BUS ± SIGNAL OPEN" or "NO RESPONSE" to indicate a communication problem. These same messages will be displayed if the vehicle is not equipped with that particular module. The CCD error message is a default message used by the DRB III and in no way indicates whether or not the PCI Bus is operational. The message is only an indication that a module is either not responding or the vehicle is not equipped.
NOTE: COMMUNICATION OVER THE BUS IS ESSENTIAL TO THE PROPER OPERATION OF THE VEHICLES ON-BOARD DIAGNOSTIC SYSTEMS AND THE DRB III. PROBLEMS WITH THE OPERATION OF THE BUS OR DRB III MUST BE CORRECTED BEFORE PROCEEDING WITH DIAGNOSTIC TESTING. IF THERE IS A PROBLEM, REFER TO THE COMMUNICATIONS CATEGORY.