M-MDS AND VEHICLE NOT COMMUNICATING [MULTIPLEX COMMUNICATION SYSTEM (R.H.D.)]

• Possible causes of communication errors between the M-MDS and vehicle include communication circuit interruption due to an open circuit in the CAN communication wiring harness, or poor contact of connector terminals, or a BUS OFF condition due to a short circuit in the CAN communication wiring harness.

• Open circuit in wiring harness between PCM and DLC-2

• Improper insertion of PCM, connector C-08, connector C-05, or connector C-11 damage, deformation, corrosion, or disconnection of connector terminals

• Short circuit in wiring harness between CAN system-related module CAN_L and CAN_H lines

• Short circuit to power supply in wiring harness between CAN system-related module

• Short circuit to ground in wiring harness between CAN system-related module

• Short circuit to power supply in CAN system-related module internal CAN lines

• Short circuit to ground in CAN system-related module internal CAN lines

• Damage, deformation, corrosion, or disconnection of DLC-2

• PCM power supply is not normal

• PCM ground is not normal

• PCM internal resistance is not normal

• CAN system-related module malfunction

Step	Inspection		Action
1	VERIFICATION BEFORE SERVICING • Is there communication between the M-MDS and vehicle?	Yes	Go to the next step.
1		No	Go back to FOREWORD [MULTIPLEX COMMUNICATION SYSTEM]. (See FOREWORD [MULTIPLEX COMMUNICATION SYSTEM (R.H.D.)].)
2	VERIFY THAT M-MDS AND DLC-2 ARE CONNECTED • Verify the connection condition between the M-MDS and DLC-2. • Are the connector terminals normal without damage, deformation, corrosion, or disconnection?	Yes	Go to the next step.
2		No	Correct the connection condition, then go to Step 12.
3	VERIFY PCM POWER SUPPLY CONDITION • Refer to the PCM terminal voltage table and inspect the terminal voltage and fuse condition. (See PCM INSPECTION [L8, LF].) • Is the power supply condition normal?	Yes	Go to the next step.
3		No	Repair or replace the fuse or wiring harness, then go to Step 12.
4	VERIFY PCM BODY GROUND CONDITION • Inspect the PCM body ground wiring harness and ground point. • Are the ground and ground point normal?	Yes	Go to the next step.
4		No	Repair or replace the wiring harness, then go to Step 12.
5	INSPECT PCM CONNECTOR TERMINAL • Disconnect the negative battery cable. • Disconnect the PCM connector. • Are the PCM connector terminal normal without damage, deformation, corrosion, or disconnection?	Yes	Go to the next step.
5		No	Repair the connector terminal if necessary, then go to Step 12.
6	INSPECT PCM • Measure the resistance between the following PCM connector terminals: ― Between terminal 1AM and terminal 1AI (part side) • Is the resistance 118-130 ohms?	Yes	Go to the next step.
6		No	Replace the PCM, then go to the next step. (See PCM REMOVAL/INSTALLATION [L8, LF].)
7	VERIFY THAT THERE IS NO OPEN CIRCUIT IN CAN COMMUNICATION WIRING HARNESS Caution • When inspecting the DLC-2, touch it with a paper clip or similar thin pin without directly inserting a tester into the terminals. • Verify the continuity between the following terminals: ― Between DLC-2 terminal F and PCM terminal 1AM ― Between DLC-2 terminal E and PCM terminal 1AI • Is there continuity?	Yes	Go to the next step.
7		No	There is an open circuit in the CAN communication wiring harness. Repair or replace it, then go to Step 12.
8	VERIFY THAT THERE IS NO SHORT CIRCUIT IN CAN COMMUNICATION WIRING HARNESS Caution • When inspecting the DLC-2, touch it with a paper clip or similar thin pin without directly inserting a tester into the terminals. • Measure the resistance between the terminals. ― Between DLC-2 terminal F and DLC-2 terminal E • Is the resistance 60 ohms or less?	Yes	There is an open circuit in the CAN communication wiring harness. Repair or replace it, then go to Step 12.
8		No	Go to the next step.
9	VERIFY NO SHORT CIRCUIT TO GROUND IN CAN COMMUNICATION WIRING HARNESS Caution • When inspecting the DLC-2, touch it with a paper clip or similar thin pin without directly inserting a tester into the terminals. • Verify the continuity between the following terminals: ― Between DLC-2 terminal F and ground ― Between DLC-2 terminal E and ground ― Between PCM terminal 1AM and ground ― Between PCM terminal 1AI and ground • Is there continuity?	Yes	There is a short circuit to ground in the CAN communication wiring harness. Repair or replace it, then go to Step 12.
9		No	Go to the next step.
10	VERIFY NO SHORT CIRCUIT TO POWER SUPPLY SYSTEM IN CAN COMMUNICATION WIRING HARNESS Caution • When inspecting the DLC-2, touch it with a paper clip or similar thin pin without directly inserting a tester into the terminals. • Verify the continuity between the following terminals: ― Between DLC-2 terminal F and DLC-2 terminal A ― Between DLC-2 terminal E and DLC-2 terminal A ― Between PCM terminal 1AM and PCM terminal 1BA ― Between PCM terminal 1AI and PCM terminal 1BA • Is there continuity?	Yes	There is a short circuit to the power supply system in the CAN communication wiring harness. Repair or replace it, then go to Step 12.
10		No	Go to the next step.
11	INSPECT CAN-RELATED MODULES OTHER THAN PCM • Remove only one of the CAN-related modules other than those related to the PCM. • Connect the negative battery cable. • Connect the M-MDS to the DLC-2. • Does the M-MDS recognize the vehicle?	Yes	Replace the removed module.
11		No	Inspect all of the CAN-related modules other than those related to the PCM using the same procedure. After inspecting all of the modules, go to the next step.
12	PERFORM VEHICLE IDENTIFICATION • Connect the M-MDS to the DLC-2. • Does the M-MDS recognize the vehicle?	Yes	DTC troubleshooting completed.
12		No	Replace the PCM. (See PCM REMOVAL/INSTALLATION [L8, LF].)