Chime/buzzer - Service Information: Overview Dodge Nitro I

Scheme 48

A chime warning system is standard factory-installed equipment. The chime warning system uses an electromechanical transducer and an electromechanical relay that are soldered onto the electronic circuit board inside of the ElectroMechanical Instrument Cluster (EMIC) (1) to provide audible indications of various vehicle conditions that may require the attention of the vehicle operator or occupants. The EMIC also includes the hardware and software necessary to serve as the electronic body control module and is sometimes referred to as the Cab Compartment Node or CCN.

The electromechanical transducer generates beep tones and chime tones, while the electromechanical relay generates click tones to emulate the sounds associated with conventional turn signal and hazard warning flasher operation. The microprocessor-based EMIC utilizes electronic chime request messages received from other modules in the vehicle over the Controller Area Network (CAN) data bus and the Local Interface Network (LIN) data bus along with hard wired inputs to monitor many sensors and switches throughout the vehicle. In response to those inputs, the circuitry and programming of the EMIC allow it to control the audible outputs that are produced through its on-board transducer and relay.

The EMIC is capable of producing the following audible outputs

1. Slow Rate Repetitive Click - Repeated click tones that are issued at a slow rate of about 90 clicks per minute.
2. Fast Rate Repetitive Click - Repeated click tones that are issued at a fast rate of more than about 180 clicks per minute.
3. Single Chime Tone - A single chime tone.
4. Slow Rate Repetitive Chime - Repeated chime tones that are issued at a slow rate of about 50 chimes per minute.
5. Fast Rate Repetitive Chime - Repeated chime tones that are issued at a fast rate of about 180 chimes per minute.

Hard wired circuitry connects the EMIC and the various chime warning system switch and sensor inputs to their modules and to each other through the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other, to the vehicle electrical system and to the EMIC through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to the SYSTEM WIRING DIAGRAMS . The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

The EMIC chime warning system circuits and components cannot be adjusted or repaired. If the EMIC circuitry, the on-board transducer or the relay are damaged or ineffective, the EMIC unit must be replaced.

Scheme 49

A park assist system is an optional factory-installed electronic parking aid. During parking and other similar vehicle maneuvers this system alerts the vehicle operator to obstacles located in the path immediately behind the vehicle which, due to the surrounding rear vehicle structure, might be otherwise difficult to perceive. When an object is detected, the system uses an electromechanical transducer and Light Emitting Diode (LED) indicators within the park assist display unit to provide the vehicle operator with visual and audible indications of the presence and proximity of such objects.

The park assist system includes the following major components, which are described in further detail elsewhere in this service information

1. Instrument Cluster (1) - In vehicles equipped with the optional park assist system, the Electronic Vehicle Information Center (EVIC) within the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) displays textual warnings and error messages and emits audible warnings related to the current operating status of the park assist system and provides an interface that allows the vehicle operator to manually disable or enable the system using the customer programmable features option.
2. Park Assist Display (4) - Vehicles equipped with the park assist system have a park assist display unit mounted in the rear of the headliner just forward of the liftgate opening. The body of the display is concealed above the headliner where it is secured by a retainer on the back of the headliner substrate. Only the narrow, oval-shaped smoked clear lens of the display is visible on the outer surface of the headliner.
3. Park Assist Module (3) - Vehicles equipped with the park assist system include a park assist module which is secured through integral mounting tabs by push-in type fasteners to the quarter inner panel above and behind the right rear wheel house where it is concealed beneath the quarter inner trim panel.
4. Park Assist Sensors (5) - Vehicles equipped with the park assist system have four ultrasonic park assist sensors that are concealed behind the rear bumper fascia. Each sensor is snapped into an individual molded plastic mounting bracket located at horizontal intervals along the back side of the rear bumper fascia.
5. Park Assist Switch (2) - The optional park assist system can be manually disabled or enabled using either a park assist switch that is integral to the instrument panel switch pod in the instrument panel center stack below the heater and air conditioner controls, or using the settings function found in the menu for the Electronic Vehicle Information Center (EVIC) of vehicles without a park assist switch in the instrument panel switch pod.

Hard wired circuitry connects the various park assist system components to each other through the electrical system of the vehicle. These hard wired circuits are integral to several wire harnesses, which are routed throughout the vehicle and retained by many different methods. These circuits may be connected to each other and to the vehicle electrical system through the use of a combination of soldered splices, splice block connectors, and many different types of wire harness terminal connectors and insulators. Refer to SYSTEM WIRING DIAGRAMS . The wiring information includes wiring diagrams, proper wire and connector repair procedures, further details on wire harness routing and retention, as well as pin-out and location views for the various wire harness connectors, splices and grounds.

The park assist system components cannot be adjusted or repaired. If any of the park assist system components is damaged or ineffective, that component must be replaced.

OPERATION

The microprocessor in the park assist module contains the park assist system logic circuits. The module uses On-Board Diagnostics (OBD) and can communicate with other electronic modules in the vehicle as well as with the diagnostic scan tool using the Controller Area Network (CAN) data bus. This method of communication is also used for park assist system diagnosis and testing through the 16-way data link connector located on the driver side lower edge of the instrument panel.

The module provides voltage to the four park assist sensors located behind the rear bumper fascia and to the park assist display located in the headliner just forward of the liftgate opening header. The module then monitors return inputs from each of the sensors and the display on dedicated hard wired data communication circuits. The sensor inputs allow the module to determine when an obstacle is in the rear path of the vehicle and enables the module to calculate the relative location of the obstacle, and whether the distance to that obstacle is increasing or decreasing.

Pre-programmed decision algorithms and calibrations allow the module microprocessor to determine the appropriate park assist system outputs based upon the inputs received from the park assist sensors and electronic messages received from other modules in the vehicle over the CAN data bus. When the programmed conditions are met the module sends electronic messages to the park assist displays over a dedicated serial bus to obtain the proper park assist system visual and audible outputs. The module also broadcasts electronic messages over the CAN data bus to enable the other electronic features of the park assist system.

The park assist module microprocessor continuously monitors all of the park assist system electrical circuits and components to determine the system readiness. If the module detects a monitored system fault, it sets a Diagnostic Trouble Code (DTC) and sends the appropriate electronic messages to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) over the CAN data bus to control operation of certain park assist system audible warnings and textual messages displayed in the Electronic Vehicle Information Center (EVIC) display of the cluster.

The park assist module receives battery current on a fused ignition switch output (run-start) circuit through a fuse in the Junction Block (JB). The module receives ground through a ground circuit and take out of the body wire harness. These connections allow the module to be operational whenever the ignition switch is in the START or ON positions.

The hard wired circuits between components related to the park assist module may be diagnosed using conventional diagnostic tools and procedures. Refer to SYSTEM WIRING DIAGRAMS . The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the park assist module or the electronic controls or communication between modules and other devices that provide some features of the park assist system. The most reliable, efficient, and accurate means to diagnose the park assist module or the electronic controls and communication related to park assist module operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

Scheme 50

1. Disconnect and isolate the battery negative cable.
2. Partially remove the trim from the right quarter inner panel to access the park assist module (2), which is located above and behind the right rear wheel house, forward of the D-pillar. Refer to «REMOVAL»(ref-306147-S42114936982008120900000) .
3. Disconnect the two body wire harness connectors (4) from the park assist module connector receptacles.
4. Remove the three plastic push-in fasteners (3) that secure the module to the right quarter inner panel (1).
5. Remove the module from the right quarter inner panel.

The park assist sensors are ultrasonic transceivers that are completely controlled by the park assist module. The sensors transmit and receive ultrasonic signals. The sensors each receive battery current and ground in parallel from the module, but are each connected to individual dedicated serial bus communication circuits to the module.

Each sensor membrane is oscillated, then quieted by the module in a pulsing fashion. While the sensor membrane oscillates, it emits an ultrasonic signal. This signal will bounce or echo off of objects in the path of the vehicle. While quieted, each membrane receives the echoes of the ultrasonic signals it and the other sensors have transmitted. The sensors then communicate this echo data over the serial bus lines back to the module. The microprocessor in the module uses the intervals between the ultrasonic transmission and reception data from the sensors to calculate the distance to any obstacles identified by the ultrasonic echoes.

The hard wired circuits between components related to the park assist sensors may be diagnosed using conventional diagnostic tools and procedures. Refer to SYSTEM WIRING DIAGRAMS . The wiring information includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention, connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods will not prove conclusive in the diagnosis of the park assist sensors or the electronic controls or communication between modules and other devices that provide some features of the park assist system. The most reliable, efficient, and accurate means to diagnose the park assist sensors or the electronic controls and communication related to park assist sensor operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.

Scheme 51

Note. The park assist sensors (3) and the sensor spacers (O-rings) are each available for separate service replacement. The sensor brackets (5) are bonded to and integral to the back side of the rear bumper fascia (2).

1. Disconnect and isolate the battery negative cable.
2. Remove the rear wheel flare and loosen the bumper fascia on the same side of the vehicle as the park assist sensor requiring service. Refer to «REMOVAL»(ref-306169-S12521720352008120900000) .
3. From the back of the fascia (2), disconnect the wire harness connector (4) from the park assist sensor (3) connector receptacle.
4. Carefully pry the sensor bracket (5) latch features (1) away from the top and bottom latch tabs of the sensor far enough to disengage the sensor from the bracket.
5. Disengage the O-ring spacer from around the circumference of the sensor membrane protrusion.

The status of the park assist switch is continually monitored by the circuitry within the instrument panel switch pod. The switch pod receives battery voltage at all times on a fused battery feed circuit, and a path to ground at all times through the instrument panel wire harness. The only other inputs to and outputs from the switch pod consist of electronic communication with the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN) over the single wire Local Interface Network (LIN) data bus.

Each time the park assist switch push button is depressed the switch pod circuitry sends an electronic park assist switch status message input to the EMIC over the LIN data bus. The EMIC then sends an electronic park assist switch request message to the park assist module over the Controller Area Network (CAN) data bus. The park assist module responds to each park assist switch request message by toggling the status of the park assist system from enabled to disabled, or from disabled to enabled, then sends an electronic park assist system status message back to the EMIC over the CAN data bus as confirmation.

The EMIC responds to the system status message by sending a message to the switch pod over the LIN data bus to control the park assist switch Light Emitting Diode (LED) unit so that the LED is illuminated with the system disabled and the ignition switch in the ON or START positions, and is extinguished with the system enabled or with the ignition switch in any position except ON or START.

The hard wired circuits between components related to the park assist switch may be diagnosed using conventional diagnostic tools and procedures. Refer to SYSTEM WIRING DIAGRAMS . However, conventional diagnostic methods will not prove conclusive in the diagnosis of the electronic controls or communication between modules and other devices that provide some features of the park assist system. The most reliable, efficient, and accurate means to diagnose the park assist switch or the electronic controls and communication related to park assist switch operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.