How to Troubleshoot The Multiplex Integrated Control System

How to Troubleshoot the Multiplex Integrated Control System

Troubleshooting CAN Circuit Related Problems

NOTE: Check the PCM for DTCs and troubleshoot PCM or F-CAN loss of communication errors first Initial Inspection and Diagnostic Overview.

Using the HDS (Preferred method)

Connect the HDS to the Data Link Connector (DLC).

NOTE: There are two ways to read B-CAN code with the HDS.

First method; Go to B-CAN System Diagnosis Test Mode A to check for DTCs Troubleshooting - B-CAN System Diagnosis Test Mode A.

Second method; Ground the SCS circuit with the HDS, then read the DTCs displayed in the multi-information display (MID) in the gauge assembly, then go to B-CAN System Diagnosis Test Mode A Troubleshooting - B-CAN System Diagnosis Test Mode A.

Without HDS (Use only if the HDS is unavailable)

1. Check for communication circuit problems using B-CAN System Diagnosis Test Troubleshooting - B-CAN System Diagnosis Test Mode 1 And Test Mode 2 (Without The HDS).

2. Check for DTCs Troubleshooting - B-CAN System Diagnosis Test Mode 1 And Test Mode 2 (Without The HDS).

NOTE: If the problem is related to the power seat control unit (with DPMS), check for DTCs first with the driving position memory system self-diagnostic function How to Troubleshoot the Driving Position Memory System (DPMS).

3. If there are multiple DTCs stored, sort them, and then troubleshoot the DTCs in this order .

1. Battery voltage DTCs

2. Internal error DTCs

3. Loss of communication DTCs

(beginning with the lowest number first; for example, if B1006 and B1059 are retrieved, troubleshoot B1006 first)

4. Signal error DTCs

4. If no DTCs are retrieved, use B-CAN System Diagnosis Test Mode 2 to check all inputs related to failure Troubleshooting - B-CAN System Diagnosis Test Mode 1 And Test Mode 2 (Without The HDS).

Loss of Communication DTC cross-reference chart

When an ECU on the CAN circuit is unable to communicate with the other ECUs on the B-CAN and F-CAN circuits, the other control units will set loss of communication DTCs. Use this chart to find the control unit that is not communicating with the other control units on the CAN circuits.

1. Find the Transmitting Control Unit that is in the same row as all of the loss of communication DTCs retrieved.

2. Do the input test for the transmitting control unit.