It is built into the underdash fuse relay box.
MODE 1 TEST
1. Remove the driver's dashboard lower cover.
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 2.
NO - Find and repair the cause of the blown fuse.
3. Turn the ignition switch ON (II).
If the driver's seatbelt is unbuckled, the seatbelt 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 inspection connector (B).
6. After about 5 seconds the spotlight and 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.
Did the spotlight and ceiling light indicate Mode 1?
YES - Go to step 8.
NO - Go to step 7.
7. Check for continuity between terminal 4 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 the DTCs are present, the spotlight and 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 spotlight and 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 instead for the DTC.
If the DTC(s) is no longer present, replace the original part.
MODE 2 TEST
1. From Mode 1, disconnect the special tool from the multiplex inspection connector for 5 to 10 seconds, and then reconnect it.
2. The spotlight and ceiling light should come on for 2 seconds, go out, then blink twice, 0.2 seconds each time. The system is now in Mode 2.
3. Operate the switches listed below. If the circuit is OK, the spotlight and ceiling lights will blink once. If the circuit is faulty, the lights will not blink.
Tip: Operate 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 single switch fails in Mode 2, troubleshoot its circuit.
MULTIPLEX SLEEP MODE TEST
1. Connect the positive lead of a voltmeter to terminal 10 of the under-dash fuse/relay box connector E (YEL) or K (WHT/GRN) and the negative lead to body ground.
2. Connect ammeter between the negative battery cable and the negative battery post.
3. Remove the special tool from the multiplex 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 approx 4 - 10 V to battery voltage and the amperage at the negative battery terminal should drop from approx. 70-80 mA to less than 10 mA.
6. Record your findings and go to the Multiplex Wake-up Test.
MULTIPLEX WAKE-UP TEST
1. From the sleep mode, Wake-up the multiplex system by performing one of the following operations:
Fig. 9: Multiplex Wake-up Test
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.
If multiplex 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. If the input test confirms that all the inputs are working properly, substitute a known-good multiplex control unit, gauge assembly or ECM one at a time. If after swapping one of the above components the system works properly, replace the original component, it is faulty.
Images (Click to enlarge)
Tuesday, January 11th, 2011 AT 3:05 PM