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 simultaneously 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.
The vehicle has 2 module communication networks connected to the Data Link Connector (DLC) and communicate with the scan tool. The communication networks are
- High Speed Controller Area Network (HS-CAN)
- Medium Speed Controller Area Network (MS-CAN)
The Infotainment Controller Area Network (I-CAN) is connected to the DLC, but the I-CAN modules communicate with the scan tool over the HS-CAN. The Instrument Panel Cluster (IPC) is used as a gateway module for the messages to transfer between the scan tool and the modules on the I-CAN.
Scheme 1
Note. Dashed lines indicate an optional module.
| Module Name | Network Type | Termination Module |
|---|---|---|
| Accessory Protocol Interface Module (APIM) (if equipped) | HS-CAN | No |
| MS-CAN (with 8-inch touchscreen) | No | |
| I-CAN | No | |
| ABS module | HS-CAN | No |
| Audio Front Control Module (ACM) | I-CAN | Yes |
| Body Control Module (BCM) (gateway) | HS-CAN | Yes |
| MS-CAN | Yes | |
| Cruise-Control Module (C-CM) (if equipped) | HS-CAN | No |
| Audio Digital Signal Processing (DSP) module (if equipped) | I-CAN | No |
| Driver Seat Module (DSM) (if equipped) | MS-CAN | No |
| Dual Climate Controlled Seat Module (DCSM) (if equipped) | MS-CAN | No |
| Front Lighting Control Module (FLM) | HS-CAN | No |
| Front Controls Interface Module (FCIM) | I-CAN | No |
| Front Control/Display Interface Module (FCDIM) (if equipped) | I-CAN | No |
| Global Positioning System Module (GPSM) (if equipped) | MS-CAN | No |
| Heated Steering Wheel Module (HSWM) (if equipped) | MS-CAN | No |
| Headlamp Control Module (HCM) (if equipped) | HS-CAN | No |
| Head Up Display (HUD) module (if equipped) | HS-CAN | No |
| HVAC module | MS-CAN | Yes |
| Instrument Panel Cluster (IPC) (gateway module) | HS-CAN | No |
| I-CAN | Yes | |
| Liftgate/Trunk Module (LTM) (if equipped) | MS-CAN | No |
| Occupant Classification System Module (OCSM) | HS-CAN | No |
| Parking Aid Module (PAM) (if equipped) | HS-CAN | No |
| PCM | HS-CAN | Yes |
| Remote Function Actuator (RFA) module (if equipped) | MS-CAN | No |
| Restraints Control Module (RCM) | HS-CAN | No |
| Steering Column Control Module (SCCM) | HS-CAN | No |
| Side Obstacle Detection Control Module - Left (SOD-L) (if equipped) | MS-CAN | No |
| Side Obstacle Detection Control Module - Right (SOD-R) (if equipped) | MS-CAN | No |
| Tire Pressure Monitor (TPM) | MS-CAN | No |
| Transmission Control Module (TCM) (if equipped) | HS-CAN | No |
Principles of Operation
The High Speed Controller Area Network (HS-CAN) operates at a maximum data transfer speed of 500 Kbps and is designed for real time powertrain information transfer and control. Modules on the HS-CAN communicate using bussed messages. The HS-CAN uses an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, the HS-CAN allows sharing of information between all modules on the network.
The Medium Speed Controller Area Network (MS-CAN) operates at a maximum data transfer speed of 125 Kbps for bus messages and is designed for general information transfer. Modules on the MS-CAN communicate using bussed messages. The MS-CAN uses an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, the MS-CAN allows sharing of information between all modules on the network.
The Infotainment Controller Area Network (I-CAN) operates at a maximum data transfer speed of 500 Kbps and is designed for real time audio and multimedia information transfer and control. Modules on the I-CAN communicate using bussed messages. The I-CAN uses an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. The I-CAN allows sharing of information between all modules on the network. The I-CAN is connected to the Data Link Connector (DLC), but the I-CAN modules communicate with the scan tool over the HS-CAN. The Instrument Panel Cluster (IPC) is used as a gateway module for the messages to transfer between the scan tool and the modules on the I-CAN.
Normal Operation
The PCM communicates with the scan tool through the High Speed Controller Area Network (HS-CAN). An Integrated Diagnostic System (IDS) session cannot be established if PCM communication fails when attempting to identify the vehicle.
This pinpoint test is intended to diagnose the following
- Wiring, terminals or connectors
- PCM
The ABS module communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- ABS module
The Restraints Control Module (RCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- Case ground open
- RCM
The Front Control/Display Interface Module (FCDIM) communicates with the scan tool through the HS-CAN. The IPC is used as a gateway module.
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- FCDIM
The Occupant Classification System Module (OCSM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- OCSM
The Headlamp Control Module (HCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- LH headlamp assembly (The HCM is serviced with the LH headlamp assembly)
The Steering Column Control Module (SCCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- SCCM
The Instrument Panel Cluster (IPC) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- IPC
The Body Control Module (BCM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN) and communicates with the other modules through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- BCM
The HVAC module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- HVAC module - EMTC
- HVAC module - DATC
The Audio Front Control Module (ACM) communicates with the scan tool through the HS-CAN. The IPC is used as a gateway module.
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- ACM
The audio Digital Signal Processing (DSP) module communicates with the scan tool through the HS-CAN. The IPC is used as a gateway module.
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- Audio DSP module
The Front Lighting Control Module (FLM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- FLM
The Liftgate/Trunk Module (LTM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- LTM
The Driver Seat Module (DSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- DSM
The Global Positioning System Module (GPSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- GPSM
The Dual Climate Controlled Seat Module (DCSM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- DCSM
The Parking Aid Module (PAM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- PAM
The Accessory Protocol Interface Module (APIM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- APIM
The Head Up Display (HUD) module communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- HUD module
The Cruise-Control Module (C-CM) communicates with the scan tool through the High Speed Controller Area Network (HS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- C-CM
The Side Obstacle Detection Control Module - Left (SOD-L) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- SOD-L
The Side Obstacle Detection Control Module - Right (SOD-R) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- SOD-R
The Tire Pressure Monitor (TPM) module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- TPM module
The FCIM communicates with the scan tool through the HS-CAN. The IPC is used as a gateway module.
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- FCIM
The Remote Function Actuator (RFA) module communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- RFA module
The Heated Steering Wheel Module (HSWM) communicates with the scan tool through the Medium Speed Controller Area Network (MS-CAN).
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- HSWM
The Transmission Control Module (TCM) communicates with the scan tool through the HS-CAN.
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- TCM
The Medium Speed Controller Area Network (MS-CAN) uses an unshielded twisted pair cable and provides the network connection to all modules on the network.
The termination modules for the MS-CAN are the BCM-HVTB and the HVAC module.
This pinpoint test is intended to diagnose the following
- Wiring, terminals or connectors
- Data Link Connector (DLC)
- Accessory Protocol Interface Module (APIM) (if equipped)
- Body Control Module (BCM)
- Dual Climate Controlled Seat Module (DCSM) (if equipped)
- Driver Seat Module (DSM) (if equipped)
- Global Positioning System Module (GPSM) (if equipped)
- Heated Steering Wheel Module (HSWM) (if equipped)
- HVAC module
- Liftgate/Trunk Module (LTM) (if equipped)
- Remote Function Actuator (RFA) module (if equipped)
- Side Obstacle Detection Control Module - Left (SOD-L) (if equipped)
- Side Obstacle Detection Control Module - Right (SOD-R) (if equipped)
- Tire Pressure Monitor (TPM) module
The High Speed Controller Area Network (HS-CAN) uses an unshielded twisted pair cable.
The termination modules for the HS-CAN are the BCM-HVTB and the PCM.
This pinpoint test is intended to diagnose the following
- Wiring, terminals or connectors
- Data Link Connector (DLC)
- ABS module
- Accessory Protocol Interface Module (APIM) (if equipped)
- Body Control Module (BCM)
- Front Lighting Control Module (FLM)
- Cruise-Control Module (C-CM) (if equipped)
- Headlamp Control Module (HCM) (if equipped)
- Head Up Display (HUD) module (if equipped)
- Instrument Panel Cluster (IPC)
- Occupant Classification System Module (OCSM)
- Parking Aid Module (PAM) (if equipped)
- PCM
- Restraints Control Module (RCM)
- Steering Column Control Module (SCCM)
- Transmission Control Module (TCM) (if equipped)
The I-CAN uses an unshielded twisted pair cable. The I-CAN is connected to the Data Link Connector (DLC), but the I-CAN modules communicate with the scan tool over the HS-CAN. The Instrument Panel Cluster (IPC) is used as a gateway module for the messages to transfer between the scan tool and the modules on the I-CAN.
The termination modules for the I-CAN are the Audio Front Control Module (ACM) and the IPC.
This pinpoint test is intended to diagnose the following
- Wiring, terminals or connectors
- Accessory Protocol Interface Module (APIM) (if equipped)
- ACM
- Audio Digital Signal Processing (DSP) module (if equipped)
- IPC
- Front Control/Display Interface Module (FCDIM) (if equipped)
- Front Controls Interface Module (FCIM)
The scan tool is connected to the Data Link Connector (DLC) to communicate with the High Speed Controller Area Network (HS-CAN), Medium Speed Controller Area Network (MS-CAN) and the Infotainment Controller Area Network (I-CAN) communication networks. A loss of ground or poor ground at the DLC may result in HS-CAN, MS-CAN or I-CAN faults while the scan tool is connected.
This pinpoint test is intended to diagnose the following
- Fuse
- Wiring, terminals or connectors
- DLC
- Scan tool
See also:
• SUPPLEMENTAL RESTRAINT SYSTEM
• SEATING