Intrepid V6-3.2L VIN J (1998)
In order for an electronic control module to communicate on the PC data bus, the module must have bus interface electronics consisting of a
transmitter/receiver (or transceiver) and Logic control, bus termination for loading and filtering the bus, and wiring which interconnects the system.
Because of the unique coding scheme used in the PCI bus, each module is required to have logic control. The data moving on the bus is called symbols.
The interface logic performs the following functions: encode and decodes binary data into symbols, synchronizes all bus symbol timing and edges,
controls the sending and receiving of messages, monitors for bus arbitration, monitors for corrupted symbols due to noise and controls the transceiver.
The bus logic control also provides the transceiver with the information it needs to transmit symbols on the bus. The transceiver controls the
waveshaping of each symbol that it transmits by using internal voltage controlled current drivers. When the bus transceiver is turned on, the bus driver
ramps up the voltage to the set range and maintains this voltage until the driver is turned off, at which time the voltage is ramped back down to the low
voltage, ground. The transceiver is design to allow for arbitration between modules. If more than one module is trying to access the PCI bus at one time,
the code determines the message that has the higher priority, and is then allowed to access the bus first.
The PCI bus requires a resistance and capacitance termination load to ground to operate. Because each bus transceiver can only source current to the bus,
the resistance load is required to sink this current and pull the bus to ground on the falling edge of the symbols. The bus resistance is minimum of 315
ohms to a maximum of 2 K ohms. The termination capacitance is required for noise filtering and to help in the symbol wave shaping. The bus
capacitance shall not be greater then 12,000 pf.
Each module on the PCI bus has a small termination load of a parallel resistance and capacitor to make up part of the over all bus termination load. One
or two modules on the PCI bus may have a higher load termination to provide stabilizing influence over the variations of vehicle builds. These modules,
called dominant modules, may very for car line to car line. The Powertrain Control Module (PCM) is the only dominant node for this vehicle.
NOTE: Communication over the bus is essential to the proper operation of the vehicles on-board diagnostic systems and the DRB. Problems with the
operation of the bus or DRB must be corrected before proceeding with diagnostic testing.
Wiper System
The wiper system provides the driver with the normal wiper (low and high speeds), intermittent wipe, wipe after wash and pulse wipe functions. The
driver selects the wiper function via the resistive multiplexed stalk switch mounted on the steering column. The Body Control Module (BCM) uses input
signal from the stalk switch, wiper motor park switch and the washer switch to control the wipe system. The BCM then controls the relays and timing
functions to provide the driver selected features.
SYSTEM FEATURES
Speed Sensitive Intermittent Wipe Mode
There are 6 individual delay times with a minimum delay of 1/2 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
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, 2 wipe cycle in low
speed mode will be provided.
Park after Ignition Off
Because the wiper relays are powered from the battery the BCM can run the wipers to park after the ignition is turned off.
Wipe after Wash
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 wipe cycles.
The wiper system utilizes the BCM to control the on/off and hi/low relays for low and hi speed wiper functions, intermittent wiper delay as the
switch position changes, pulse wipe, wipe after wash mode, and wiper motor park functions. The BCM uses the vehicle speed input to double the
usual delay time below 10 MPH There are three diagnostic trouble codes associated with the wiper system. Two codes are set based on the
condition of the on/oft relay control wire open, shorted to ground or shorted to battery. The third code will set if the wiper motor park switch fails
to open and close.
