This is a communication issue between modules.
You will need an advanced scan tool and experience with the system to track the issue. This could be a simple as a connection issue or a module issue but needs to be verified.
I posted the description and possibilities for you to view.
NOTE: The Smart Junction Box (SJB) is also known as the Generic Electronic Module (GEM).
Vehicle communication utilizes both High Speed (HS) and Medium Speed (MS) Controller Area Network (CAN) communications. 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 onto a single network. Information is sent to individual control modules that control each function.
The vehicle has 2 module communication networks:
High Speed Controller Area Network (HS-CAN)
Medium Speed Controller Area Network (MS-CAN)
Both 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 both networks from one connector. The DLC can be found under the instrument panel.
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Module Name Network Type Termination Module
ABS HS-CAN No
Accessory Protocol Interface Module (APIM) (if equipped) HS-CAN / MS-CAN No
Audio Control Module (ACM) MS-CAN No
Front Controls Interface Module (FCIM) MS-CAN No
Front Display Interface Module (FDIM) MS-CAN No
HVAC module MS-CAN No
Instrument Cluster (IC) (gateway module) HS-CAN MS-CAN Yes Yes
Occupant Classification System Module (OCSM) HS-CAN No
PCM HS-CAN Yes
Restraints Control Module (RCM) HS-CAN No
Smart Junction Box (SJB) MS-CAN Yes
Medium Speed Controller Area Network (MS-CAN) Operation
The MS-CAN communicates using bussed messages. The MS-CAN has an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, this network allows sharing of information between all modules on the network.
The MS-CAN is a medium speed communication network used for the following modules:
APIM (if equipped)
High Speed Controller Area Network (HS-CAN) Operation
The HS-CAN communicates using bussed messages. The HS-CAN uses an unshielded twisted pair cable, data bus (+) and data bus (-) circuits. In addition to scan tool communication, this network allows sharing of information between all modules on the network.
The HS-CAN is a high speed communication network used for the following modules:
APIM (if equipped)
The CAN uses a network termination circuit to improve communication reliability. The network termination of the CAN bus takes place inside the termination modules by termination resistors. Termination modules are located at either end of the bus network. As network messages are broadcast in the form of voltage signals, the network voltage signals are stabilized by the termination resistors. Each termination module has a 120 ohm resistor across the positive and negative bus connection in the termination module. With 2 termination modules on each network, and the 120 ohm resistors located in a parallel circuit configuration, the total network impedance, or total resistance is 60 ohms.
Network termination improves bus message reliability by:
stabilizing bus voltage.
Eliminating electrical interference.
The IC is the gateway module, translating HS-CAN to MS-CAN and vice versa. This information allows a message to be distributed throughout both networks. The IC is the only module on this vehicle that has this ability.
Images (Click to enlarge)
Thursday, July 23rd, 2020 AT 5:55 AM