Inspection Procedure 29
Power supply system and ignition switch - IG system.Power Supply And Ignition Switch-IG Circuit:
Connectors:
CIRCUIT OPERATION
- Battery positive voltage is applied to the MFI relay (terminals 1, 2).
- When the ignition switch is turned to the "ON" position, the battery positive voltage is applied to the ECM (terminal 99)
- Battery positive voltage is constantly supplied to the ECM (terminal 60)
- The ECM (terminal 46, 58)
TROUBLESHOOTING HINTS (The most likely causes for this code to be set are:)
- Malfunction of the ignition switch.
- Malfunction of the MFI relay.
- Improper connector contact, open circuit or short-circuited harness wire.
- Disconnected ECM
- Malfunction of the ECM
DIAGNOSIS
STEP 1. Check connector A-18X at MFI relay for damage.
Q: Is the connector in good condition?
YES: Go to Step 2.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 2. Check the MFI relay.
1. Remove the MFI relay.
2. Check for continuity between the MFI relay terminals 2 and 3.
- There should be continuity, (approximately 70 Ohm)
3. Use jumper wires to connect MFI relay terminal 2 to the positive battery terminal and terminal 3 to the negative battery terminal.
4. Check the continuity between the MFI relay terminals 1 and 4 while connecting and disconnecting the jumper wire at the negative battery terminal.
- Should be less than 2 ohm. (Negative battery terminal connected)
- Should be open loop. (Negative battery terminal disconnected)
5. Install the MFI relay.
Q: Is the voltage normal?
YES: Go to Step 3.
NO: Replace the MFI relay. Then confirm that the malfunction symptom is eliminated.
STEP 3. Check the power supply voltage at MFI relay harness side connector A-18X.
1. Disconnect the connector A-18X and measure at the harness side.
2. Measure the voltage between terminal 1, 2 and ground.
- Voltage should be battery positive voltage.
Q: Is the voltage normal?
YES: Go to Step 4.
NO: Check harness connector C-07 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connector is in good condition, repair harness wire between fusible link 3. and MFI relay connector A-18X terminal 1, 2 because of open circuit. Then confirm that the malfunction symptom is eliminated.
STEP 4. Check connector C-62 at ECM
Q: Is the connector in good condition?
YES: Go to Step 5.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 5. Check the ignition switch - IG signal voltage at ECM harness side connector C-62
1. Disconnect the connector C-62
2. Turn the ignition switch to the "ON" position.
3. Measure the voltage between terminal 99
- 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 6.
NO: Check harness connector C-07, C-89, C-112 and C-111 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connectors are in good condition, repair harness wire between ignition switch connector C-87 terminal 2 and ECM connector C-62 terminal 99
STEP 6. Check the backup power supply voltage at ECM harness side connector C-58
1. Disconnect the connector C-58
2. Measure the voltage between terminal 60
- Voltage should be battery positive voltage.
Q: Is the voltage normal?
YES: Go to Step 7.
NO: Check harness connector C-28, C-78 and C-89 at intermediate connector for damage, and repair or replace as required. Refer to Harness Connector Inspection. If intermediate connectors are in good condition, repair harness wire between fusible link (18) and ECM connector C-58 terminal 60
STEP 7. Check the continuity at ECM harness side connector C-58
1. Disconnect the connector C-58
2. Check for the continuity between terminal (46, 58)
- Should be less than 2 ohm.
Q: Is the continuity normal?
YES: Go to Step 8.
NO: Repair harness wire between ECM connector C-58 terminal (46, 58)
STEP 8. Check the power supply voltage at ECM harness side connector C-58
1. Disconnect the connector C-58
2. Measure the voltage between terminal 57
- Voltage should be battery positive voltage.
Q: Is the voltage normal?
YES: Go to Step 9.
NO: Repair harness wire between MFI relay connector A-18X terminal 3 and ECM connector C-58 terminal 57
STEP 9. Check the power supply voltage at ECM harness side connector C-58
1. Disconnect the connector C-58
2. Using a jumper wire, connect terminal 57
3. Measure the voltage between terminal (47, 59)
- Voltage should be battery positive voltage.
Q: Is the voltage normal?
YES: Replace the ECM or PCM. Then confirm that the malfunction symptom is eliminated.
NO: Repair harness wire between MFI relay connector A-18X terminal 4 and ECM connector C-58 terminal (47, 59)