How to Troubleshoot the MICU

NOTE: Use only if the HDS is unavailable.

System Description


Test Mode 1


The B-CAN communication line can be checked by the Test Mode 1, and the ceiling light indicates a DTC with the blinking pattern.

Test Mode 2


Test Mode 2 can check the switch and sensor circuits connected to the MICU. Some switch and sensor circuits connected to the gauge control module (tach) and immobilizer-keyless control unit can check also when the B-CAN line is normal.

 

Test Mode 1


Special Tools Required
MPCS short connector (  07WAZ-0010100)
 



1.Check the No. 16 (15 A) fuse in the under-hood fuse/relay box and the No. 10 (7.5 A) fuse in the under-dash fuse/relay box. If the fuse is blown, find and correct the cause, then replace the fuse.

2.Remove the driver's dashboard lower cover.

3.Turn the ceiling light switch in ‘‘DOOR'' (middle) position. Close all doors. Turn the ignition switch ON (II). If the driver's seat belt is unbuckled, the beeper will beep.

4.Connect the MPCS short connector (A) to the MICU service check connector (B), and turn the switch (C) on.

 

5.After 5 seconds, the ceiling light should come on for 2 seconds, go out, then blink once for 0.2 second. This means that you are in Test Mode 1 of the self-diagnostic function.

NOTE: If the ceiling light does not come on and blink, check if the SCS circuit works properly.

6.About 1 second after step 5, the ceiling light will blink and 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:

DTC Cause and Troubleshooting 
1 The MICU cannot receive signals sent from the MICU itself (for checking the sending signals), or the MICU cannot receive signals from the gauge control module (tach). If DTC 1 only indicates, substitute a known-good gauge control module (tach) and an MICU one at a time, in that order, and recheck for the DTC after each substitution. 


How to cancel the Test Mode 1


NOTE: To cancel Test Mode 1, turn off the MICU short connector switch for more than 10 seconds or turn the ignition switch OFF.

Test Mode 2


1.While in Test Mode 1, turn off the MPCS short connector switch (A) for about 5 to 10 seconds, then turn it on again.

 

2.The ceiling light should come on for 2 seconds, go out, then blinks twice more at 0.2 second intervals. This means the system has gone from Test Mode 1 to Test Mode 2.

3.While still in Test Mode 2, operate the switches in the table below. If the circuit is OK, the ceiling light blinks once. If the circuit is faulty, the ceiling light does not blink.

  • If the ceiling light does not blink even a switch is operated, check two or three other circuits listed in the table. If the ceiling light blinks for each circuit, the additional circuits are OK, repair the short or open circuit that failed the test in 3.
  • If the ceiling light does not blink again, this multiple failed circuits mean that the control unit has failed without triggering a DTC. Test a few more circuits. If they also fail, test the MICU input test. If all the input tests prove OK, substitute a known-good MICU or gauge control module (tach) one at a time, then recheck. If the system works properly, the part that was substituted is faulty; replace it.

Driver's door lock switch (UNLOCK) Windshield wiper MIST switch 
Driver's door lock switch (LOCK) Windshield washer switch 
Driver's door lock knob switch (UNLOCK) Windshield wiper intermittent dwell time controller 
Driver's door lock knob switch (LOCK) Turn signal switch (LEFT) 
Driver's door key cylinder switch (UNLOCK) Turn signal switch (RIGHT) 
Driver's door key cylinder switch (LOCK) Hazard warning switch 
Front passenger's door lock switch (UNLOCK) Headlight switch (ON) 
Front passenger's door lock switch (LOCK) Headlight switch (OFF) 
Front passenger's door lock knob switch (UNLOCK) Lighting switch 
Left rear door lock knob switch (UNLOCK) Dimmer switch 
Right rear door lock knob switch (UNLOCK) Passing switch 
Driver's door switch Hood switch (with security) 
Front passenger's door switch Brake pedal position switch 
Left rear door switch Tailgate handle switch 
Right rear door switch  Front fog light switch 
Tailgate latch switch Rear fog light switch 
Audio switch Ignition key switch 
Windshield wiper HI/LO switch  
Windshield wiper INT/LO switch  


How to cancel the Test Mode 2


NOTE: To cancel Test Mode 2, disconnect the MPCS short connector from the multiplex control inspection connector for more than 10 seconds or turn the ignition switch OFF.