Part 3 of 4
DIAGNOSIS AND TESTINGSelf-check Diagnostics
1. With the ignition switch in the OFF position, depress and hold the STEP button.
2. Turn the ignition switch to the ON position and release the STEP button.
3. All of the VFD segments will illuminate for 2 - 4 seconds. Check for segments that do not illuminate or illuminate all the time.
4. The self-check is complete when an F (FAIL), or a P (PASS) is displayed. If an F is displayed, the overhead console must be replaced. The CTM will not display an F for a VF segment that does not illuminate.
5. To exit the self-check mode, depress the STEP button or cycle the ignition switch and the Compass/Temperature Module will return to normal operation.
Ambient Temperature Sensor
The outside temperature function is supported by the ambient temperature sensor (ATS), a signal and ground circuit hardwired to the compass/temp module, and the display.
If the display indicates 60 °C (140 °F) or the ATS sense circuit is shorted to ground, the temp display will be 60 °C (140 °F) to indicate a SHORT circuit condition.
If the display indicates -45 °C (-49 °F) or the ATS sense circuit is open, the temp display will be -45 °C (-49 °F) to indicate an OPEN circuit condition.
If there is an OPEN or SHORT circuit condition, it must be repaired before the VF display can be tested.
The ATS can be diagnosed using the following Sensor Test. Test the ATS circuits using the diagnostics in the Body Diagnostic Procedures Manual. If the ATS and the circuits are confirmed to be OK, but the temperature display is inoperative or incorrect, replace the Compass/Temperature Module.
Ambient Temperature Sensor Test
1. Turn the ignition OFF.
2. Disconnect and isolate the battery negative cable.
3. Disconnect the ATS harness connector.
4. Measure the resistance of the ATS using the following min/max values:
Ambient Temperature Sensor Resistance
0 °C (32 °F) 29.33 - 35.99 Kilohms
10 °C (50 °F) 17.99 - 21.81 Kilohms
20 °C (68 °F) 11.37 - 13.61 Kilohms
25 °C (77 °F) 9.12 - 10.86 Kilohms
30 °C (86 °F) 7.37 - 8.75 Kilohms
40 °C (104 °F) 4.90 - 5.75 Kilohms
The sensor resistance should read between these min/max values. If the resistance values are not OK, replace the Sensor.
INSTRUMENT CLUSTER
The instrument cluster for the PT/PG 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 continually 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 immediately and the instrument cluster to turn the courtesy lamps ON when the vehicle reaches 0 MPH.
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, 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 IOD fuse may be removed.
VEHICLE THEFT SECURITY SYSTEM
When the VTSS is armed, it monitors the status of the ignition switch and ajar switches for the vehicle doors and liftgate. If the alarm is tripped, it will sound the vehicles horn, flash the exterior lamps and the VTSS indicator located in the instrument cluster.
Arming the system is accomplished by locking the doors with the door lock switch following a normal exit sequence of opening the door, pressing the power lock button and closing the door, by using a cylinder lock switch or by pressing the RKE lock button. After all the doors are closed, the VTSS indicator will flash quickly for 16 seconds indicating the pre-arm process, after which it will flash at a slower rate indicating the system is armed. If during the pre-arm process a door is opened, the ignition is turned to the Run/Start position, or if the RKE module receives an unlock request, the system will automatically be disarmed.
Disarming can be accomplished with a RKE unlock, turning the ignition ON with a valid Sentry key or unlocking the vehicle with a cylinder lock switch. All of the switches 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.
Vehicle Theft Security System (Export Only)
The VTSS is available in either a base or premium configuration. Both systems will monitor the ignition switch status, ajar switches for the vehicle doors, liftgate and hood. In addition to this the premium system will monitor the interior of the vehicle for movement via an intrusion sensor. When tripped to the alarming state, the exterior lights and VTSS indicator will flash along with cycling of the vehicle horn for the base system while the premium version uses a battery backed siren for the audible alert.
Arming the system is accomplished by locking the doors with the door lock switch following a normal exit sequence of opening the door, pressing the power lock button and closing the door, or by using any cylinder lock switch, or by pressing the RKE lock button. After all the doors are closed, the VTSS indicator will flash quickly for 16 seconds indicating the pre-arm process, after which it will flash at a slower rate indicating the system is armed. If during the pre-arm process a door is opened, the ignition is turned to the Run/Start position, or if the RKE module receives an unlock request, the system will automatically be disarmed. If the VTSS indicator stays ON steady during pre-arm, it is an indication of the hood ajar circuit being shorted (hood opened). Defeating the intrusion sensor feature for vehicles so equipped can be done by three additional lock requests within 5 seconds of each other during the pre-arming process to the RKE module from either the RKE fob or a cylinder lock switch.
Disarming is done by either a RKE unlock or turning the ignition ON with a valid Sentry key or from any cylinder lock switch for certain markets. All of the switches 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 (If Equipped)
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 (24 kph), 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.