Multiplex Control System Troubleshooting/DTC Troubleshooting: P0600 (39-1)
Special Tool Required:
MPCS Service Connector ( 07WAZ-0010100)
|1.||Check the No. 9 (10 A) fuse in the under-hood fuse/relay box and the No. 10 (7.5 A) fuse in the under-dash fuse/relay box.|
Are the fuses OK?
YES - Go to 2.
NO - Find and repair the cause of the blown fuse.n
|2.||Remove the driver's dashboard lower cover.|
|3.||Switch the ceiling light to the middle position. Close all doors. Turn the ignition switch ON (II).|
If the driver's seatbelt is unbuckled, the beeper will beep five times.
|4.||Check self-diagnosis function Mode 1 for a diagnostic trouble code (DTC) by connecting the special tool (A) to the multiplex control inspection connector (B). After about 5 seconds, the ignition switch light and ceiling light should come on for 2 seconds, go out, then blink once for 0.2 second. This means that you are in Mode 1 of the self-diagnosis function.|
Did the blinking lights confirm that you are in model?
YES - Count the blinks, then go to 5.
NO - See if the SCS circuit is working properly. Go to 6.
|5.||If there is a DTC, it will blink, pause, then repeat the DTC as long as the ignition switch is ON (II).|
Is there continuity?
YES - Count the blinks, then go to 8.
NO - Go to 9.
|6.||Check for continuity between the inspection connector T1 and body ground.|
Is there continuity?
YES - Go to 9.
NO - Go to 7.
|7.||Check for continuity between the connector J of under-dash fuse/relay box No. 4 terminal and body ground.|
Is there continuity?
YES - Faulty under-dash fuse/relay box. Replace and check for DTCs.
NO - Repair the open in the wire, and recheck for DTCs.n
|8.||About 1 second after you go into self-diagnosis mode 1, the ceiling light will indicate the DTC, and repeat it every 3 seconds. If there is more than one DTC, the system will indicate them in ascending order, beginning from the DTC with the lowest numerical value. Troubleshoot the DTCs as indicated below:|
|9.||From Mode 1, disconnect the special tool from the multiplex control inspection connector for about 5 to 10 seconds, then reconnect it. The ceiling light should come on for 2 seconds, then blink twice more at 0.2 second intervals. This means the system has gone from Mode 1 to Mode 2.|
MODE 2: Ceiling Light Blinking Pattern
|10.||Look in the following table for the switches most closely related to the problem. While still in Mode 2, operate the switches and the control unit. If the circuit is OK, the spotlight and ceiling light should blink once. If the circuit is faulty, there will be no indication.|
Does the ceiling light blink?
YES - Go to 12.
NO - Go to 11.
|11.||Check two or three other circuits listed above.|
Does the spotlight and ceiling light blink for each circuit?
YES - The additional circuits are OK. Repair the short or open in the circuit that failed the test in step 10.n
NO - Multiplex failed circuits can mean that the control unit has failed, but without triggering a DTC. Test a few more circuits. If they also fail, test the multiplex control unit inputs. If all the input test are OK, substitute a known-good control unit, gauge assembly, or ECM/ PCM, one at a time, then recheck. If the system works properly, the original control unit is faulty; replace it. If there is still a malfunction, substitute a known-good control unit for the next most likely faulty control unit, then recheck. If the system works properly, that control unit is faulty; replace it.n
|12.||Shift to the sleep mode:|
Turn the ignition switch OFF, and remove the key.
If the control unit receivers no inputs from the inputs listed below, it will go into the sleep mode after about 20 seconds.
|13.||Comfirm the sleep mode:|
Check for voltage on the YEL and WHT/GRN wires. There should be battery voltage in the sleep mode. Check the parasitic draw at the battery while shifting into the sleep mode. Amperage should change from about 70 through 80 mA to less than 10 mA.
|14.||Shift to the wake up mode:|
When the ignition switch is turned ON (II), the multiplex control unit, gauge assembly, and ECM/PCM wake up at the same time without ‘‘talking'' to each other through the communication lines. When any switch in the multiplex system is turned on, it wakes up its related control unit which, in turn, wakes up the other units.
After confirming the sleep mode, look in the following table for the switch most closely related to the problem. Operate that switch and see if its control unit wakes up.
NOTE: If any control unit is faulty and will not wake up, several parts of the system will malfunction at the same time.
In the table below, the control unit is followed by a list of the switches and input signals that can wake it up.
Is the wake-up function OK?
YES - Intermittent failure; the system is OK at this time.