Overview
Multiplexing is a method of sending 2 or more signals simultaneously over a single circuit. Multiplexing allows 2 or more electronic modules (nodes) to communicate over a twisted wire pair [data (+) and data (-)] network. The information or messages that can be communicated on these wires consists of commands, status or data. The advantage of using multiplexing is to reduce the weight of the vehicle by reducing the number of redundant components and electrical wiring.
Note. The Infotainment Controller Area Network (I-CAN) goes to the DLC , but the Infotainment Controller Area Network (I-CAN) modules communicate with the scan tool over the Medium Speed Controller Area Network (MS-CAN). The IPC is used as a gateway module for the messages to transfer between the scan tool and the modules on the Infotainment Controller Area Network (I-CAN).
The vehicle has 3 module communication networks connected to the DLC , located under the instrument panel. The communication networks are
- High Speed Controller Area Network (HS-CAN)
- Medium Speed Controller Area Network (MS-CAN)
- Infotainment Controller Area Network (I-CAN)
Fault Tolerance Normal Operation
The data (+) and data (-) circuits are each regulated to approximately 2.5 volts during neutral or rested network traffic. As messages are sent on the data (+) circuit, voltage is increased by approximately 1.0 volt. Inversely, the data (-) circuit is reduced by approximately 1.0 volt when a message is sent.
Successful communication of a message can usually be identified by the slight spike at the end of a message transmission. Any signals that are significantly different than the normal CAN waveform may cause network Diagnostic Trouble Codes (DTCs) (U-codes) to set or may cause a complete network outage.
Normal Operation and Fault Conditions
The PCM communicates with the diagnostic scan tool through the HS-CAN . An IDS session cannot be established if the PCM communication fails when attempting to identify the vehicle.
The ABS module communicates with the diagnostic scan tool through the HS-CAN .
The BCM communicates with the diagnostic scan tool through the HS-CAN and communicates with the other modules through the MS-CAN .
The IPC communicates with the diagnostic scan tool through the MS-CAN and communicates with the other modules on the Infotainment Controller Area Network (I-CAN).
The PSCM communicates with the diagnostic scan tool through the HS-CAN .
The RCM communicates with the diagnostic scan tool through the HS-CAN .
The OCSM communicates with the diagnostic scan tool through the HS-CAN .
The SASM communicates with the diagnostic scan tool through the HS-CAN .
The PAM communicates with the diagnostic scan tool through the HS-CAN .
The RFA module communicates with the diagnostic scan tool through the MS-CAN .
The APIM communicates with the diagnostic scan tool and other network modules on the HS-CAN and Infotainment Controller Area Network (I-CAN) (4.2-inch screen). The APIM also communicates with other network modules on the MS-CAN (8-inch touchscreen).
The ACM communicates with the diagnostic scan tool through the HS-CAN . The IPC is used as the gateway module.
The FCIM communicates with the diagnostic scan tool through the HS-CAN . The IPC is used as the gateway module.
The FCDIM communicates with the diagnostic scan tool through the HS-CAN . The IPC is used as the gateway module.
The GPSM communicates with the diagnostic scan tool through the MS-CAN .
The SODL and SODR communicate with the diagnostic scan tool through an extended MS-CAN to the BCM . The BCM translates the messages to the diagnostic scan tool.
The DSM communicates with the diagnostic scan tool through the MS-CAN .
The HVAC module communicates with the diagnostic scan tool through the MS-CAN .
The DSP communicates with the diagnostic scan tool through the HS-CAN . The IPC is used as the gateway module.
The Headlamp Control Module (HCM) communicates with the diagnostic scan tool through the HS-CAN .
The DDM communicates with the diagnostic scan tool through the MS-CAN .
The PDM communicates with the diagnostic scan tool through the MS-CAN .
The RGTM communicates with the diagnostic scan tool through the MS-CAN .
The IPMB communicates with the diagnostic scan tool through the MS-CAN .
The TRM communicates with the diagnostic scan tool through the MS-CAN .
Refer to: COMMUNICATIONS NETWORK - SYSTEM OPERATION AND COMPONENT DESCRIPTION.
Refer to: COMMUNICATIONS NETWORK - SYSTEM OPERATION AND COMPONENT DESCRIPTION.
Refer to: COMMUNICATIONS NETWORK - SYSTEM OPERATION AND COMPONENT DESCRIPTION.
The diagnostic scan tool is connected to the DLC to communicate with the HS-CAN , MS-CAN and the Infotainment Controller Area Network (I-CAN) communication networks. A loss of ground or poor ground at the DLC can result in HS-CAN , MS-CAN or Infotainment Controller Area Network (I-CAN) faults while the diagnostic scan tool is connected.