LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Honda >> 2021 >> Odyssey EX >> Repair and Diagnosis >> Engine Performance >> Engine Control Systems >> Engine Control System / Engine Mechanical - Service, Testing And Troubleshooting >> Troubleshooting >> MIL Circuit Troubleshooting
April 5, 2026: LEMON Manuals is launched! Read the announcement.

MIL Circuit Troubleshooting

  1. Gauge control module check

    -1. Turn the vehicle to the ON mode.

    -2. Do the gauge control module self-diagnostic function .

    Does the MIL flash?

    YES 

    Go to step 2.

    NO 

    Substitute a known-good gauge control module , then recheck. If the symptom/indication goes away with a known-good gauge control module, replace the original gauge control module .

  2. PCM check

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Connect the HDS to the DLC .

    -3. Turn the vehicle to the ON mode.

    -4. Check the parameter(s) below with the HDS.

    Signal Threshold Current conditions
    Values Unit Values Unit
    SCS Short      

    Do the current condition(s) match the threshold?

    YES 

    Go to step 3.

    NO 

    Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If the symptom/indication goes away and the PCM was substituted, replace the original PCM .

  3. Shorted wire check (SCS line)

    -1. Turn the vehicle to the OFF (LOCK) mode.

    -2. Jump the SCS line with the HDS, and wait more than 1 minute.

    -3. Disconnect the following connector.

    PCM connector A (50P)

    -4. Disconnect the HDS from the DLC.

    -5. Check for continuity between test points 1 and 2.

    Test condition Vehicle OFF (LOCK) mode
      PCM connector A (50P): disconnected
    Test point 1 PCM connector A (50P) No. 45 
    Test point 2 Body ground

    Is there continuity?

    YES 

    Repair a short in the SCS wire between the PCM (A45) and the DLC.

    NO 

    The SCS wire is OK. Check for any authorized service information related to the DTCs or symptoms you are troubleshooting, or substitute a known-good PCM , then recheck. If the symptom/indication goes away and the PCM was substituted, replace the original PCM .