Multiplex Control System: Diagnosis Honda CR-V II

Troubleshooting

Special Tools Required

MPCS service connector 07WAZ-001010A

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1. Remove the driver's dashboard lower cover (see «DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTAL»(ref-171400-S16959782682005020300000) ).
2. Check the No. 9 (10A) fuse in the under-hood fuse/ relay box and the No. 10 (7.5A) fuse in the under-dash fuse/relay box. Are the fuses OK ? YES - Go to step 3. NO - Find and repair the cause of the blown fuse.
3. Turn the ignition switch ON (II). If the driver's seat belt is unbuckled, the seat belt reminder will chime 6 times.
4. Set the ceiling light to the center position and close all the doors.
5. Connect the special tool (A) to the multiplex control inspection connector (B).
6. After about 5 seconds, the front ceiling light should come on for 2 seconds, go out, then blink on for 0.2 second to show the system is now in Mode 1. MODE 1: Did the front ceiling light indicate Mode 1? YES - Go to step 8 . NO - Go to step 7.
7. Check for continuity between No. 4 terminal of the under-dash fuse/relay box connector J and body ground. Is there continuity? YES - Replace the under-dash fuse/relay box. NO - Repair the open in the wire. If the wire is OK, repair G301.
8. If there are any DTCs present, the front ceiling light will blink to indicate the DTC(s). If more than one DTC is present, the DTCs will be displayed in ascending order. If there are no DTCs, the front ceiling light will not blink again after the Mode 1 indication. Are there any DTCs? YES - Go to step 9. NO - Go to the Mode 2 test.
9. Troubleshoot the DTC(s) in the order indicated using the following charts. If a faulty control unit is suspected, substitute it with a known good part and recheck for DTCs. If the DTC(s) is still present, go to the next step listed for the DTC. If the DTC(s) is no longer present replace the original part. Multiple DTCs

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1. From Mode 1, disconnect the special tool from the multiplex control inspection connector for 5 to 10 seconds, and then reconnect it.
2. The front ceiling light should come on for 2 seconds, go out, then blink twice, 0.2 second each time. The system is now in Mode 2. MODE 2
3. Operate the switches listed below: If the circuit is OK, the front ceiling light will blink once. If the circuit is faulty, the lights will not blink. Tip: Operating the switches most closely related to the problem you are diagnosing is a quick way of testing the circuits integrity.
4. If all inputs were confirmed, or multiple circuits failed at the same time in Mode 2, go to the multiplex sleep mode test, If a singe switch fails in Mode 2, troubleshoot its circuit.

Multiplex Sleep Mode Test

1. Connect the positive lead of a voltmeter to No. 10 terminal of the under-dash fuse/relay box connector E (YEL) or K (WHT/GRN) and the negative lead to body ground.
2. Connect an ammeter between the negative battery cable and the negative battery post.
3. Remove the special tool from the multiplex control inspection connector.
4. Close the doors, the hatch, turn the headlights off, turn off the ignition switch and remove the key.
5. Within 1 minute, the voltage on the communication wire (E10 or K10) should change from about 4-10 V to battery voltage and the amperage at the negative battery terminal should drop from about 70-80 mA to less than 10 mA.
6. Record your findings and go to the Multiplex Wake-up Test.

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1. From the sleep mode, wake-up the multiplex system by performing one of the following operations
2. As the system shifts to its active (wake-up) mode, communication wire voltage will return to 4-10 V and the battery terminal current will return to 70-80 mA.
3. If the system does not go into sleep mode or wake-up properly, perform the Multiplex Control Unit Input Test (see «Multiplex Control Unit Input Test»(ref-172186-S08350761312005022200000) ).

Note. If multiple circuits fail to respond in the mode 2 tests and/or the multiplex circuit fails to go into sleep mode or wake-up, it may mean that a control unit failed without triggering a DTC in mode 1. Perform the Multiplex Control Unit Input Test (see Multiplex Control Unit Input Test ). If the input test confirms that all the inputs are working properly, substitute a known-good multiplex control unit, gauge assembly, the keyless receiver unit, or ECM/PCM one at a time. If the system works properly after swapping one of the above components, replace the original component, it is faulty.

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1. Remove the driver's dashboard lower cover (see «DRIVER'S DASHBOARD LOWER COVER REMOVAL/INSTALLATION»(ref-171400-S16959782682005020300000) ).
2. Disconnect the under-dash fuse/relay box connectors C, E, F, J, K, O, P, Q, X and Y. NOTE: All connectors are wire side of female terminals.
3. Inspect the connector and socket terminals to be sure they are all making good contact. If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system. If the terminals look OK, go to step 4.
4. Reconnect the connectors to the under-dash fuse/relay box, and make sure these input tests at the appropriate connectors on the under-dash fuse/relay box. If any test indicates a problem, find and correct the cause, then recheck the system. If all the input tests prove OK, the multiplex control unit must be faulty, replace the under-dash fuse/relay box assembly.

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