Inspection Procedure 31
Ignition Switch-ST SystemIgnition Switch-ST Circuit:
Connectors:
CIRCUIT OPERATION
- The battery positive voltage is supplied to the ECM (terminal 71) via the starter relay during engine cranking. With this, the ECM detects that the engine is being cranked.
TROUBLESHOOTING HINTS (The most likely causes for this case:)
- Malfunction of the ignition switch.
- Malfunction of the starter relay.
- Improper connector contact, open circuit or short-circuited harness wire.
- Malfunction of the ECM.
DIAGNOSIS
STEP 1. Check connector B-07X at starter 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 starter relay.
Refer to Starting system - On-vehicle Service - Starter relay check.
Q: Are there any abnormalities?
YES: Go to Step 3.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 3. Check the power supply voltage at starter relay connector B-07X.
1. Disconnect the connector B-07X and measure at the harness side.
2. Turn the ignition switch to the "START" position.
3. Measure the voltage between terminal 2, 3 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 4.
NO: Check connector C-123 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 ignition switch connector C-201 terminal 5 and starter relay connector B-07X terminal 2, 3 because of open circuit. Then confirm that the malfunction symptom is eliminated.
STEP 4. Check connector C-420 at ECM for damage.
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 power supply voltage at ECM connector C-115.
1. Disconnect the connector C-115 and measure at the harness side.
2. Turn the ignition switch to the "START" position.
3. Measure the voltage between terminal 71 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 6.
NO: Repair harness wire between starter relay connector B-07X terminal 5 and ECM connector C-115 terminal 71 because of open circuit. Then confirm that the malfunction symptom is eliminated.
STEP 6. Check connector C-131 at interlock switch for damage.
Q: Is the connector in good condition?
YES: Go to Step 7.
NO: Repair or replace it. Refer to Harness Connector Inspection. Then confirm that the malfunction symptom is eliminated.
STEP 7. Check the interlock switch.
Refer to On-vehicle Service - Interlock switch check and adjustment.
Q: Are there any abnormalities?
YES: Go to Step 8.
NO: Repair or replace it. Then confirm that the malfunction symptom is eliminated.
STEP 8. Check the power supply voltage at interlock switch connector C-131.
1. Disconnect the connector C-131 and measure at the harness side.
2. Turn the ignition switch to the "START" position.
3. Measure the voltage between terminal 2 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 9.
NO: Check connector C-124 and C-129 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 starter relay connector B-07X terminal 1 and interlock switch connector C-131 terminal 2 because of open circuit. Then confirm that the malfunction symptom is eliminated.
STEP 9. Check the continuity at interlock switch harness side connector C-131.
1. Disconnect the connector C-131 and measure at the harness side.
2. Check for the continuity between terminal 1 and ground.
- Should be less than 2 ohm.
Q: Is the continuity normal?
YES: Replace the ECM. Then confirm that the malfunction symptom is eliminated.
NO: Repair harness wire between interlock switch connector C-131 terminal 1 and ground because of open circuit or harness damage. Then confirm that the malfunction symptom is eliminated.