Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Communications Network: Notes
Vehicle communication utilizes both International Standards Organization (ISO) 9141 and controller area network (CAN) communications. ISO 9141 is used for diagnostic use only while CAN allows many modules to communicate with each other on a common network. CAN in-vehicle networking is a method for transferring data among distributed electronic modules via a serial data bus.
Without serial networking, intermodule communication requires dedicated, point to point wiring resulting in bulky, expensive, complex, and difficult to install wiring harnesses. Applying a serial data network reduces the number of wires, combining the signals on a single network. Information is sent to the individual control modules that control each function.
The vehicle has 3 module communication networks:
- ISO 9141
- Medium speed (MS) CAN
- High speed (HS) CAN
All 3 networks are connected to the data link connector (DLC). This makes diagnosis and testing of these systems easier by allowing one scan tool to be able to diagnose and control any module on the 3 networks from one connector. The DLC can be found under the instrument panel between the steering column and the audio control module (ACM).
| Module Name | Network Type | Termination Module |
|---|---|---|
| Audio control module (ACM) | MS-CAN | No |
| ABS module | HS-CAN | No |
| Heating ventilation air conditioning (HVAC) module | MS-CAN | No |
| Front controls interface module (FCIM) (if equipped) | MS-CAN | No |
| Front display interface module (FDIM) | MS-CAN | No |
| Instrument cluster (IC) (gateway module) | HS-CAN MS-CAN |
Yes Yes |
| Occupant classification system module (OCSM) | HS-CAN | No |
| Parking aid module (PAM) (if equipped) | ISO 9141 | N/A |
| PCM | HS-CAN | Yes |
| Power steering control module (PSCM) | HS-CAN | No |
| Restraints control module (RCM) | HS-CAN | No |
| Satellite digital audio receiver system (SDARS) module | MS-CAN | No |
| Smart junction box (SJB) | MS-CAN | Yes |
| 4X4 control module (if equipped) | HS-CAN | No |
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.