Inspection Procedure 3

Connectors:

CIRCUIT OPERATION
- The service engine soon/malfunction indicator lamp power is supplied from the ignition switch.
- The PCM controls the ground of the service engine soon/malfunction indicator lamp by turning the power transistor in the PCM ON and OFF.

COMMENT
- The PCM causes the service engine soon/malfunction indicator lamp to illuminate for 5 seconds immediately after the ignition switch is turned to the "ON" position occurred.

TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Burnt-out bulb.
- Defective service engine soon/malfunction indicator lamp circuit.
- Malfunction of the PCM.

DIAGNOSIS

Required Special Tool:
MB991502: Scan Tool (MUT-II)




STEP 1.Using scan tool MB991502, check data list item 16: Power Supply Voltage.

CAUTION: To prevent damage to scan tool MB991502, always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting scan tool MB991502.

1. Connect scan tool MB991502 to the data link connector.
2. Turn the ignition switch to the "ON" position.
3. Set scan tool MB991502 to the data reading mode for item 16, Power Supply Voltage.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage normal?

YES: Go to Step 2.

NO: Refer to INSPECTION PROCEDURE 28 - Power Supply System and Ignition Switch-IG System.

STEP 2.Check the burned-out bulb.

Q: Is the valve normal?

YES: Go to step 3.

NO: Replace the bulb. Then confirm that the malfunction symptom is eliminated.




STEP 3.Check harness connector C-04 at the combination meter for damage.

Q: Is the harness connector in good condition?

YES: Go to step 4.

NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.




STEP 4.Cheek the power supply voltage at combination meter harness side connector C-04.
1. Disconnect the connector C-04 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 24 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage normal?

YES: Go to Step 5.

NO: Check harness connectors D-06 and D-08 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connectors D-06 and D-08 are in good condition, repair it because of open circuit between ignition switch connector D-15 terminal 2 and combination meter connector C-04 terminal 24.Then confirm that the malfunction symptom is eliminated.




STEP 5.Check harness connector C-89 at the PCM for damage.

Q: Is the harness connector in good condition?

YES: Go to Step 6.

NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.




STEP 6.Check the power supply voltage at PCM connector C-89.
1. Disconnect the connector C-89 and measure at the harness side.
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 22 and ground.
- Voltage should be battery positive voltage.
4. Turn the ignition switch to the "LOCK" (OFF) position.

Q: Is the voltage normal?

YES: Replace the PCM. Then confirm that the malfunction symptom is eliminated.

NO: Check harness connector C-16 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connector C-16 is in good condition, repair an open circuit between combination meter connector C-04 terminal 23 and PCM connector C-89 terminal 22.Then confirm that the malfunction symptom is eliminated.