Part 2 of 2
SELF-CHECK DIAGNOSTICSThe EVIC is capable of performing a diagnostic self check on its internal functions. EVIC diagnostics may be performed using a DRBIII(R) or by using the following procedure:
1. With the ignition switch in the OFF position, depress and hold the RESET and the C/T buttons.
2. Turn the ignition switch to the ON position.
3. Continue to hold both buttons until the software versions are displayed, then release the buttons.
4. When the self-check is complete the EVIC will display one of the following messages:
- PASSED SELF TEST
- FAILED SELF TEST
- FAILED J1850 COMMUNICATION
5. To exit the self-check mode, depress the RESET button or cycle the ignition switch and the EVIC will return to normal operation.
If a Communication fault is displayed, refer to the symptom list. If a FAILED SELF TEST is displayed, the EVIC must be replaced.
AMBIENT TEMPERATURE SENSOR
The ambient air temperature is monitored by the PCM and displayed by the EVIC. The PCM receives a hardwire input from the ambient temperature sensor (ATS).
The ATS is a variable resistor that operates on a 5-volt reference signal circuit hardwired from the PCM. The resistance in the ATS changes as the outside temperature rises or falls. The PCM senses the change in reference voltage through the ATS resistor. Based on the resistance of the ATS, the PCM is programmed to correspond to a specific temperature. The PCM stores and filters the ambient temperature data and transmits this data to the EVIC via the PCI Bus. The ATS cannot be adjusted or repaired and, if faulty or damaged, it must be replaced.
AMBIENT TEMPERATURE SENSOR FAULT CODES
The outside temperature function is supported by the ambient temperature sensor (ATS), a signal and ground circuit hardwired to the PCM, and the EVIC display
If the EVIC display indicates 54°C (130°F) or the ATS sense circuit is shorted to ground, the temp display will be 54°C (130°F) to indicate a SHORT circuit condition.
If the EVIC display indicates -40°C (-40°F) or the ATS sense circuit is open, the temp display will be -40°C (-40°F) to indicate an OPEN circuit condition.
If there is an OPEN or SHORT circuit condition, it must be repaired before the EVIC VFD can be tested.
The ATS is supported by the PCM. Ambient Temperature Sensor DTCs will be recorded in the PCM. Test the ATS circuits using the diagnostics in the Powertrain Diagnostics Procedures.
AMBIENT TEMPERATURE SENSOR TEST
1. Turn the ignition OFF.
2. Disconnect the ATS harness connector.
3. Measure the resistance of the ATS using the following min/max values:
- 0°C (32°F) Sensor Resistance = 29.33 - 35.99 Kilohms
- 10°C (50°F) Sensor Resistance = 17.99 - 21.81 Kilohms
- 20°C (68°F) Sensor Resistance = 11.37 - 13.61 Kilohms
- 25°C (77°F) Sensor Resistance = 9.12 - 10.86 Kilohms
- 30°C (86°F) Sensor Resistance = 7.37 - 8.75 Kilohms
- 40°C (104°F) Sensor Resistance = 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.
HOMELINK(R) UNIVERSAL TRANSMITTER
If equipped, the HomeLink(R) Universal Transmitter is integrated into the overhead console. For added security it will operate home security systems that use coded signals known generically as Rolling Codes. The overhead console display provides visual feedback to the operator, indicating which HomeLink(R) transmitter channel button is being pressed. The HomeLink(R) can learn and store up to 3 separate transmitter radio frequency codes to operate garage door openers, security gates, and security lighting. The HomeLink(R) buttons are marked with one, two, or three dots. For complete information, refer to Universal Transmitter.
POWER DOOR LOCKS/REMOTE KEYLESS ENTRY (RKE)
The BCM controls the Power Door Locks via the relays in the JB. There are three individual relays for this system: Driver Unlock Relay, which only unlocks the drivers door, the Unlock Relay which unlocks the other 3 doors, and the Lock Relay, which locks all of the doors.
There are two Power Door Lock Switches (on the driver and passenger doors) which are read by the BCM to control the locks.
The optional RKE module plugs directly into the side of a highline BCM. A lowline BCM does not have a connector for the RKE. The RKE receiver communicates with the RKE transmitters (key fobs), and gives the BCM commands, via a direct serial communications line. The RKE can tell the BCM to unlock the doors, lock the doors, open the flip-up glass, or initiate the panic alarm. The RKE also can be used to change the Customer Programmable Features (such as Enable / Disable Optical Chirp).
The BCM will actuate the Lock Relay for 250 ms if either power lock switch is in the lock position, unless the driver's door is ajar and the key is in the ignition. The BCM will also lock the doors if the RKE lock button is pressed.
The BCM will actuate the Driver's Door Unlock Relay and the Unlock All Relay for 250 ms if either power lock switch is in the unlock position. If the Customer Programmable Features are set to Unlock Driver's Door First, the BCM will only actuate the Driver's Door Unlock Relay when the RKE Unlock button is pressed the first time If the button is pressed a second time, both the unlock relays will be actuated (2 unlock presses within 5 seconds). However, if the Customer Programmable Features are set to Unlock All Doors, then the BCM actuates both unlock relays every time an RKE unlock button is pressed.
The BCM does not allow rapid cycling of the lock / unlock relays. Once the BCM starts to actuate a lock or unlock relay, it will hold it for 250 ms regardless of someone cycling the switch rapidly.
The BCM will lock the doors if the Customer Programmable Feature for Rolling Locks is enabled, and the PCI bus message from the Powertrain Control Module (PCM) is received.
The BCM also directly drives the Tailgate Lock motor and the Flip-up Glass Release motor. The BCM can reverse the current through the Tailgate Lock motor to lock or unlock the door as required. If the BCM actuates the Flip-up Glass Release motor, the latch on the glass is released, and the window will raise itself under the power of two gas cylinders (struts).
The Tailgate motor will be controlled to the lock or unlock positions exactly the same as the conditions above for the Door Lock Relay. In addition, the Tailgate Motor will be locked for the following conditions:
1. Tailgate Cylinder Lock Switch in the lock position (if equipped).
2. Battery disconnect / reconnect (including pulling and replacing the IOD fuse)
3. Rear Wiper Switch turned on
The Tailgate Motor can also be unlocked with the Tailgate Cylinder Lock Switch (if equipped).
The Flip-Up Glass Release Motor will release the latch if the Tailgate Cylinder Lock Switch is turned to the unlock position (if equipped) or the RKE Flip-Up Glass button is pressed or the BCM "knows" the doors are unlocked and the rear door handle is pulled to the Flip-Up Glass Release position.
This vehicle is not equipped with central locking. The key cylinder lock switches, if equipped, are to disarm the VTSS only.
REAR WINDOW DEFOGGER
The Body Control Module reads the Rear Window Defogger Switch and turns on the rear window defogger relay to defrost the rear glass. The first time in an ignition cycle that the driver presses the defogger button, the BCM will turn on the relay for 10 minutes. The second and subsequent times, the BCM will turn on the relay for 5 minutes. If the ignition is turned off, the BCM will turn the rear window defogger relay off.
VEHICLE THEFT SECURITY SYSTEM (VTSS)
The BCM controls the VTSS if equipped. To arm the VTSS the BCM will begin the VTSS Pre-arming process, which last for sixteen seconds after the following criteria is met. The key is removed from the ignition switch and the operator locks the vehicle using a key fob or power door lock switch with the doors closed or if the doors are open it will then begin when all doors are closed. During Pre-arm, the VTSS indicator located in the Instrument Cluster flashes two times per second. Pre-arm is exited if any door/tailgate is opened, flip-up glass is opened, a cylinder lock switch is turned to unlock, or the ignition is turned on.
After the Pre-arm timer expires, the BCM goes to the armed mode and flashes the VTSS indicator at a slower rate. The BCM monitors the door ajar, flip-up glass ajar, tailgate ajar and ignition status and trips to alarming if any of these change states.
Disarming the VTSS feature is done with the left key cylinder lock switch, a Remote Keyless Entry system "unlock" or the ignition turned to the "on" position with a valid SKIM key.
If the BCM is triggered to the Alarm state, it flashes the headlamps, hazard lamps and actuates the Horn on and off for 3 minutes, then will flash the headlamps and hazard lamps without the horn for an additional 15 minutes until it times out.
After the timeout, the alarm will return to the armed state. If the alarm was triggered while the operator was away from the vehicle, the BCM will chirp the horn 3 times ("Tamper Alert") when the driver disarms the alarm.
VEHICLE THEFT SECURITY SYSTEM (VTSS) (EXPORT ONLY)
The Vehicle Theft Security System (VTSS) is available in either a base or a premium version for this model. The base system is controlled by the Body Control Module (BCM) while the premium system is controlled by the BCM along with an Intrusion Transceiver Module (ITM) which monitors the interior of the vehicle for movement. The base VTSS uses the vehicle horn for the audible alert while the premium version is equipped with a battery backed siren. Both systems will flash the hazard lamps when tripped. The VTSS does not prevent engine operation, this is done with the Sentry Key Immobilizer System SKIS. For information regarding SKIS, refer to the appropriate Powertrain Diagnostic Procedures.
To arm the VTSS the BCM must complete a sixteen-second Pre-arming process, which will begin after the following criteria are met. The key is removed from the ignition switch and the operator locks the vehicle using a key fob or power door lock switch with the doors, tailgate and flip-up glass closed or if any of these are open, pre-arm will begin after they are closed. If the hood is left open during pre-arming it will be ignored as input until it is closed. During Pre-arming, the VTSS indicator located in the Instrument Cluster flashes two times per second. Pre-arm is exited if any doors, tailgate, flip-up glass or the hood is opened, or if the ignition switch is turned to the on position.
After the Pre-arming timer expires, the BCM goes to the armed mode and flashes the VTSS indicator at a slower rate. The BCM will then monitor the ignition switch status along with the hood/door/flip-up glass/tailgate ajar switches. For vehicles equipped with the Intrusion Transceiver Module the vehicle's interior will continuously be monitored for movement. This feature can be disabled during the pre-arm sequence with three additional lock commands from the RKE which will cause a single audible chirp confirming this request. While armed the Siren will continuously monitor it's battery feed and the siren signal control circuits and will trigger if either of these are disconnected. The Siren also sends a status message back to the ITM.
Disarming the VTSS is done with either a Remote Keyless Entry system "unlock" or the ignition turned to the "on" position with a valid SKIM key.
When the VTSS is triggered on a base system, the alarming state will be twenty-five seconds. Vehicles with the premium system will actuate the hazard lamps for twenty-five seconds and the siren twenty-eight seconds. After that period if the disturbance is still present only the siren will be activated again for twenty-eight seconds with five seconds intervals between warning cycles. This will continue up to ten times unless the disturbance goes away. If the alarm was triggered while the operator was away from the vehicle, there will be three audible chirp messages when the system is disarmed.
WINDSHIELD WIPER SYSTEM (FRONT)
The BCM controls the Front Windshield Wipers via the On/Off and Hi/Low relays located in the Power Distribution Center (PDC), based on input from the Front Wiper Mode Switch. NOTE: The BCM does not control the rear wiper system, however, the BCM does monitor the Rear Wiper Mode Switch to control the flip-up glass release. This function is discussed under Power Door Locks.
If the Front Wiper Mode Switch is in any of the Intermittent Delay positions, the BCM will turn on the On/ Off relay until the wiper motor is off of the Park Switch. The internal wiring between the motor and the relays, allows the wipers to complete a single cycle and return to the parked position. The BCM monitors the Park Switch to make sure that the Wiper is able to return to the parked position within 8 seconds. If this does not occur, the BCM sets a Wiper Park Switch DTC and turns the wiper on/off relay to on until the wipers are switched off.
If the Front Wiper Mode Switch is in the Low position, the BCM will turn on the On/Off relay. The wiper motor will run at low speed.
If the Front Wiper Mode Switch is in the High position, the BCM will turn on the On/Off relay and the Hi/Low relay. The wiper motor will run at high speed.
If the Front Wiper Mode Switch is turned to the Wash position, the BCM will turn on the On/Off relay until it sees 3 cycles of the park switch. The wiper motor will run at low speed for 3 cycles and then resume whatever the current mode of the switch is.
THE BCM IS ALSO INVOLVED IN THE FOLLOWING FUNCTIONS:
VEHICLE SPEED SENSING
The speed sensor on the rear axle generates approximately 80,000 pulses per mile. This signal is sent to the ABS module (if equipped) and then to the BCM, The BCM has been programmed in the Assembly Plant with the proper tire size. If a BCM is replaced, it must be programmed with the proper tire size using the DRBIII(R). Based on this tire size, the BCM converts the 80,000 pulses per mile into 8,000 pulses per mile, and outputs this signal to the PCM,
If the vehicle is equipped with ABS, the ABS module supplies the required 12VDC to the wheel speed sensor. If the vehicle is not equipped with ABS, the BCM supplies this voltage on the Vehicle Speed Sensor Supply pin. This output is on for non-ABS vehicles when the ignition switch is in the Run or Crank positions.
DETECTION / ANALYSIS OF MISCELLANEOUS BODY SWITCHES
The BCM detects the position of the A/C Switch from the control head and reports this over the PCI bus to the PCM.
The BCM detects the position of the Renegade Lighting Input and reports this over the PCI bus to the Cluster.
DRIVER INFORMATION WARNINGS (CHIME)
The Chime is located in the cluster. However, the cluster goes to sleep with the ignition off, so the BCM turns on the Cluster Wake-up Output when it detects that the Headlamps-On Warning or the Key-In-Ignition Warning conditions exist. The BCM sends these warnings to the Cluster over the PCI bus.