MIL Does Not Come ON with Ignition Switch in ON Position and Engine Stopped (but Engine Can Be Started)

MIL Does Not Come ON with Ignition Switch in ON Position and Engine Stopped (but Engine Can Be Started)

Wiring Diagram










Circuit Description

When the ignition switch is turned to ON position, ECM causes the main relay to turn ON (close the contact point). Then, ECM being supplied with the main power, transmits indication ON signal of MIL to combination meter in order to turn ON MIL. And then, combination meter turns ON MIL. When the engine starts to run and no malfunction is detected in the system, ECM transmits MIL indication OFF signal to combination meter in order to turn OFF MIL. And then, combination meter turns OFF MIL, but if a malfunction was or is detected, MIL remains ON even when the engine is running.

Troubleshooting

1. MIL power supply check

Turn ignition switch to ON position.

Do other warning lights come ON?
YES -
Go to Step 2.
NO -
Go to Step 4.

2. DTC check in ECM

Turn OFF ignition switch and connect scan tool to DLC.
Turn ignition switch to ON position and check DTC in ECM.

Is there DTC(s) U0073 and/or U0121?
YES -
Go to troubleshooting for applicable DTC.
NO -
Go to Step 3.

3. DTC check in BCM

Check DTC in BCM.

Is there DTC U0100?
YES -
Go to troubleshooting for applicable DTC.
NO -
Substitute a known-good combination meter and recheck. If MIL still remains OFF, substitute a known-good ECM and recheck.

4. CAN communication line circuit check

Check CAN communication line circuit between control modules for open, short, high resistance and connections referring to Step 1 of "Troubleshooting" under Troubleshooting for Communication Bus Off Troubleshooting for Communication Bus Off.

Is circuit in good condition?
YES -
Go to Step 5.
NO -
Repair or replace defective wire harness.

5. "METER" fuse check

Turn ignition switch to OFF position.
Check if "METER" fuse in junction block is blown.

Is "METER" fuse in good condition?
YES -
Go to Step 6.
NO -
Replace "METER" fuse and check for short.

6. Combination meter power supply circuit check

Remove combination meter. Service and Repair
Check for proper connection to combination meter connector at combination meter power supply circuit and combination meter ground circuit.
If OK, then turn ignition switch to ON position and measure voltage between combination meter power supply circuit (A1) and vehicle body ground.

Is it 10 - 14 V?
YES -
Go to Step 7.
NO -
Repair or replace defective wire harness.

7. Combination meter ground circuit check

Turn OFF ignition switch.
Measure resistance between combination meter ground circuit (B1) and vehicle body ground.

Is resistance 1 ohms or less?
YES -
Substitute a known-good combination meter and recheck. If MIL still remains OFF, substitute a known-good ECM and recheck.
NO -
Repair or replace defective wire harness.