Multiplex Communication System[Multiplex Communication System]: Flowchart

WARNING: This page is about a different car, the 2007 Mazda MX-5 Miata. However, it is still accessible from the selected car via links, so may be relevant.

Use the following flowchart to verify the cause of the trouble.

MULTIPLEX COMMUNICATION SYSTEM INSPECTION FLOWCHART

STEP	INSPECTION		ACTION
1	INSPECT DTC INDICATION Using the M-MDS, inspect if DTCs are displayed for the following module: PCM TCM DSC HU/CM ABS HU/CM Power retractable hardtop control module Keyless control module Steering angle sensor Instrument cluster Are any DTCs displayed?	Yes	Go to the next step.
1		No	Go to Step 5.
2	INSPECT CAN SYSTEM-RELATED DTC Are any DTCs other than the following displayed? U0073 U0100 U0101 U0121 U0155 U0207 U0214 U0323 U1900 U2023 U2197 U2516	Yes	Repair the malfunctioning part by following the related DTC inspection. Go to the next step.
2		No	Go to the next step.
3	INSPECT CAN SYSTEM-RELATED DTC Are any of the following DTCs displayed? PCM: U0073, U0101, U0121, U0155 TCM: U0073, U0100 DSC HU/CM: U0073, U0100, U0101, U0155, U1900, U2023 ABS HU/CM: U0073, U1900, U2023 Power retractable hardtop control module: U0073, U0100, U0101, U2197 Keyless control module: U0073, U0100, U0207, U0323, U2023 Steering angle sensor: U1900, U2516 Instrument cluster: U0073, U0100, U0101, U0121, U0214	Yes	Repair the malfunctioning part by following the DTC inspection. Go to the next step.
3		No	Troubleshooting completed.
4	VERIFY TROUBLESHOOTING COMPLETED Clear the DTC from the CAN system-related modules using the M-MDS. Start the engine. Are any of the CAN related DTCs displayed?	Yes	Go back to Step 3.
4		No	Troubleshooting completed.
5	INSPECT COMMUNICATION CONDITION Is there a response from the following modules? PCM TCM DSC HU/CM ABS HU/CM Power retractable hardtop control module Keyless control module Steering angle sensor Instrument cluster	Yes	Troubleshooting completed
5		No	Go to the next step.
6	INSPECT MODULES THAT DO NOT RESPOND Inspect the power supply and the ground circuit for any units that do not respond. Are they normal?	Yes	Go to the next step.
6		No	Repair the malfunctioning part, then go back to Step 1.
7	INSPECT CONNECTOR AND WIRING HARNESS BETWEEN MODULES THAT DO NOT RESPOND AND DLC-2 Turn the ignition switch to the LOCK position. Inspect the wiring harness and connector between any module that does not respond and the DLC-2. PCM-DLC-2 - 1AM-F - 1AI-E TCM-DLC-2 - 1G-F - 1C-E DSC HU/CM-DLC-2 - X-F - W-E ABS HU/CM-DLC-2 - Z-F - Y-E Power retractable hardtop control module-DLC-2 - 3S-F - 3U-E Keyless control module-DLC-2 - 4AA-F - 4Z-E Steering angle sensor-DLC-2 - E-F - F-E Instrument cluster-DLC-2 - 1J-F - 1L-E Is there any malfunction?	Yes	Repair the malfunctioning part, then go back to Step 1.
7		No	Go to the next step.
8	INSPECT WIRING HARNESS Turn the ignition switch to the ON position (Engine off). Measure the voltage between the following terminals. - DLC-2 terminals F and GND - DLC-2 terminals E and GND Is the voltage 2.0-3.0 V?	Yes	Go to the next step.
8		No	Go to Step 12.
9	INSPECT WIRING HARNESS Turn the ignition switch to the LOCK position. Measure the resistance between the following terminals. - DLC-2 terminals F and E Is the resistance 59-65 ohms?	Yes	Replace the modules that do not respond, then go back to Step 1.
9		No	Go to the next step.
10	INSPECT PCM Disconnect the PCM connector. Measure the resistance between following terminals. - PCM terminals 1AM and 1AI (part-side) Is the resistance 118-130 ohms?	Yes	Go to the next step.
10		No	Replace the PCM, then go to the next step.
11	INSPECT INSTRUMENT CLUSTER Disconnect the instrument cluster connector. Measure the resistance between the following terminals. - Instrument cluster terminals 1J and 1L (part-side) Is the resistance 118-130 ohms?	Yes	Go to next step.
11		No	Replace the instrument cluster, then go to the next step.
12	CLASSIFY WIRING HARNESS MALFUNCTION OR MODULE MALFUNCTION Turn the ignition switch to the LOCK position. Disconnect the connector of any unit that does not respond. (If there are two or more units that do not respond, disconnect only one of the units.) Turn the ignition switch to the ON position. Measure the voltage between the following terminals. - DLC-2 terminals F and GND - DLC-2 terminals E and GND Is voltage 2.0-3.0 V?	Yes	Go to the next step.
12		No	Retry this step with other module connector disconnected. If all units that do not respond are disconnected, go to Step 14.
13	INSPECT WIRING HARNESS OF ANY UNIT THAT DOES NOT RESPOND Turn the ignition switch to the LOCK position. Inspect for continuity between the following connector terminals of any disconnected unit. PCM-DLC-2 - 1AM-other terminals - 1AI-other terminals TCM-DLC-2 - 1G-other terminals - 1C-other terminals DSC HU/CM-DLC-2 - X-other terminals - W-other terminals ABS HU/CM-DLC-2 - Z-other terminals - Y-other terminals Power retractable hardtop control module-DLC-2 - 3S-other terminals - 3U-other terminals Keyless control module-DLC-2 - 4AA-other terminals - 4Z-other terminals Steering angle sensor-DLC-2 - E-other terminals - F-other terminals Instrument cluster-DLC-2 - 1J-other terminals - 1L-other terminals Is there continuity?	Yes	Repair or replace the wiring harness, then go back to Step 1.
13		No	Replace the disconnected unit, then go back to Step 1.
14	INSPECT CAN RELATED WIRING HARNESS Inspect the related wiring harnesses (CAN_L and/or CAN_H) for the short circuit (to power supply or ground). Is the wiring harness normal?	Yes	Repair or replace the wiring harness, then go back to Step 1.
14		No	Go back to Step 1.