Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
MICU Input Test (2018-19)
- Before testing, check for DTCs. If any DTCs are indicated, troubleshoot those DTCs first.
- If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A - Refer to: Body Electrical Troubleshooting - B-CAN System Diagnosis Test Mode A - Initial Communication and DTC Checks (2018-19) .
- Before testing, make sure the No. A29 (10 A) fuse in the under-hood fuse/relay box are OK.
- Before testing, make sure the No. B5 (7.5 A) fuse in the under-dash fuse/relay box is OK.
1. Turn the vehicle to the OFF (LOCK) mode
2. Disconnect under-dash fuse/relay box connectors. Under-dash fuse/relay box connector A (5P) (female terminals) :
Under-dash fuse/relay box connector D (44P) (female terminals) :
Under-dash fuse/relay box connector E (36P) (female terminals) :
Under-dash fuse/relay box connector M (12P) (female terminals) :
Under-dash fuse/relay box connector P (24P) (female terminals) :
Under-dash fuse/relay box connector R (16P) (female terminals) :
3. Inspect the connectors 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 are OK, go to step 4.
4. With the connectors still disconnected, do the following input tests:
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 5.
| Cavity | Wire | Test condition | Test: Desired result | Possible cause if desired result is not obtained |
|---|---|---|---|---|
| M4 | PNK | Disconnect the power window master switch 37P connector | Check for continuity between terminal M4 and power window master switch 37P connector terminal No. 28: There should be continuity. |
An open in the B-CAN wire |
| M5 | BLU | Check for continuity between terminal M5 and power window master switch 37P connector terminal No. 30: There should be continuity. |
||
| M4 *1 | PNK | Disconnect the audio unit connector A (24P) | Check for continuity between terminal M4 and audio unit connector A (24P) terminal No. 4: There should be continuity. |
An open in the B-CAN wire |
| M5 *1 | BLU | Check for continuity between terminal M5 and audio unit connector A (24P) terminal No. 2: There should be continuity. |
||
| M4 *2 | PNK | Disconnect the audio-navigation unit connector A (24P) | Check for continuity between terminal M4 and audio-navigation unit connector A (24P) terminal No. 4: There should be continuity. |
An open in the B-CAN wire |
| M5 *2 | BLU | Check for continuity between terminal M5 and audio-navigation unit connector A (24P) terminal No. 2: There should be continuity. |
||
| M4 | PNK | Disconnect the keyless access/TPMS control unit connector C (20P) | Check for continuity between terminal M4 and keyless access/TPMS control unit connector C (20P) terminal No. 1: There should be continuity. |
An open in the B-CAN wire |
| M5 | BLU | Check for continuity between terminal M5 and keyless access/TPMS control unit connector C (20P) terminal No. 11: There should be continuity. |
||
| M4 | PNK | Disconnect the gauge control module 32P connector | Check for continuity between terminal M4 and gauge control module 32P connector terminal No. 25: There should be continuity. |
An open in the B-CAN wire |
| M5 | BLU | Check for continuity between terminal M5 and gauge control module 32P connector terminal No. 26: There should be continuity. |
||
| M4 | PNK | Disconnect the climate control unit connector A (40P) | Check for continuity between terminal M4 and climate control unit connector A (40P) terminal No. 20: There should be continuity. |
An open in the B-CAN wire |
| M5 | BLU | Check for continuity between terminal M5 and climate control unit connector A (40P) terminal No. 40: There should be continuity. |
||
| M4 | PNK | Disconnect the power seat control unit connector A (20P) | Check for continuity between terminal M4 and power seat control unit connector A (20P) terminal No. 16: There should be continuity. |
An open in the B-CAN wire |
| M5 | BLU | Check for continuity between terminal M5 and power seat control unit connector A (20P) terminal No. 17: There should be continuity. |
||
| M4 *3 | PNK | Disconnect the automatic lighting/rain sensor 5P connector | Check for continuity between terminal M4 and automatic lighting/rain sensor 5P connector terminal No. 4: There should be continuity. |
An open in the B-CAN wire |
| M5 *3 | BLU | Check for continuity between terminal M5 and automatic lighting/rain sensor 5P connector terminal No. 3: There should be continuity. |
||
| M4 *4 | PNK | Disconnect the automatic lighting control unit-sensor 5P connector | Check for continuity between terminals M4 and automatic lighting control unit-sensor 5P connector terminal No. 1: There should bee continuity. |
An open in the B-CAN wire |
| M5 *4 | BLU | Check for continuity between terminals M5 and automatic lighting control unit-sensor 5P connector terminal No. 2: There should bee continuity. |
||
| M4 *5 | PNK | Disconnect the parking and back-up sensor control unit 16P connector | Check for continuity between terminal M4 and parking and back-up sensor control unit 16P connector terminal No. 9: There should be continuity. |
An open in the B-CAN wire |
| M5 *5 | BLU | Check for continuity between terminal M5 and parking and back-up sensor control unit 16P connector terminal No. 2: There should be continuity. |
||
| M4 *6 | PNK | Disconnect the left side BSI radar unit 6P connector | Check for continuity between terminal M4 and left side BSI radar unit 6P connector terminal No. 3: There should be continuity. |
An open in the B-CAN wire |
| M5 *6 | BLU | Check for continuity between terminal M5 and left side BSI radar unit 6P connector terminal No. 5: There should be continuity. |
||
| M4 *6 | PNK | Disconnect the right side BSI radar unit 6P connector | Check for continuity between terminal M4 and right side BSI radar unit 6P connector terminal No. 3: There should be continuity. |
An open in the B-CAN wire |
| M5 *6 | BLU | Check for continuity between terminal M5 and right side BSI radar unit 6P connector terminal No. 5: There should be continuity. |
||
| M4 *7 | PNK | Disconnect the multi view camera unit 20P connector | Check for continuity between terminal M4 and multi view camera unit 20P connector terminal No. 19: There should be continuity. |
An open in the B-CAN wire |
| M5 *7 | BLU | Check for continuity between terminal M5 and multi view camera unit 20P connector terminal No. 20: There should be continuity. |
||
| M4 | PNK | Disconnect the multipurpose camera unit 20P connector | Check for continuity between terminal M4 and multipurpose camera unit 20P connector terminal No. 6: There should be continuity. |
An open in the B-CAN wire |
| M5 | BLU | Check for continuity between terminal M5 and multipurpose camera unit 20P connector terminal No. 17: There should be continuity. |
||
| M4 *8 | PNK | Disconnect the telematics control unit connector A (36P) | Check for continuity between terminal M4 and telematics control unit connector A (36P) terminal No. 33: There should be continuity. |
An open in the B-CAN wire |
| M5 *8 | BLU | Check for continuity between terminal M5 and telematics control unit connector A (36P) terminal No. 34: There should be continuity. |
||
| M4 *9 | PNK | Disconnect the ventilated seat control unit 14P connector | Check for continuity between terminal M4 and ventilated seat control unit 14P connector terminal No. 11: There should be continuity. |
An open in the B-CAN wire |
| M5 *9 | BLU | Check for continuity between terminal M5 and ventilated seat control unit 14P connector terminal No. 10: There should be continuity. |
||
| M4 *10 | PNK | Disconnect the front seat heater control unit 14P connector | Check for continuity between terminals M4 and front seat heater control unit 14P connector terminals No. 11: There should be continuity. |
An open in the B-CAN wire |
| M5 *10 | BLU | Check for continuity between terminals M5 and front seat heater control unit 14P connector terminals No. 10: There should be continuity. |
||
| M4 *11 | PNK | Disconnect the wireless charger 7P connector | Check for continuity between terminal M4 and wireless charger 7P connector terminal No. 3: There should be continuity. |
An open in the B-CAN wire |
| M5 *11 | BLU | Check for continuity between terminal M5 and wireless charger 7P connector terminal No. 2: There should be continuity. |
||
| R12 | LT BLU | Under all conditions | Check for continuity between terminal R12 and data link connector (DLC) terminal No. 7: There should be continuity. |
An open in the K LINE wire |
*1: With audio
*2: With navigation
*3: With automatic wiper
*4: Without automatic wiper
*5: With parking and back-up sensor system
*6: With BSI
*7: With multi view camera system
*8: With AcuraLink
*9: With ventilated seat
*10: Without ventilated seat
*11: With wireless charger
5. Reconnect the connectors to the under-dash fuse/relay box, and do the following input tests:
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, the MICU must be faulty; replace the under-dash fuse/relay box .
| Cavity | Wire | Test condition | Test: Desired result | Possible cause if desired result is not obtained |
|---|---|---|---|---|
| E23 | WHT | Under all conditions | Measure the voltage to ground: There should be battery voltage. |
|
| A1 | BRN | Vehicle ON mode | Measure the voltage to ground: There should be battery voltage. |
|
| D3 | BLK | In all power modes | Measure the voltage to ground: There should be less than 0.2 V. |
|
| D30 | BLK | In all power modes | Measure the voltage to ground: There should be less than 0.2 V. |
|
| E6 | BLK | In all power modes | Measure the voltage to ground: There should be less than 0.2 V. |
|
| P1 | BLK | In all power modes | Measure the voltage to ground: There should be less than 0.2 V. |
|
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.