Inspection Procedure 5: Horns do not sound while the security alarm system is triggered.
COMMENTS ON TROUBLE SYMPTOM
PROBABLE CAUSES
- Horns may be defective
- Horn relay may be defective
- The ETACS-ECU may be defective
- The wiring harness or connectors may have loose, corroded, or damaged terminals, or terminals pushed back in the connector
DIAGNOSIS PROCEDURE |
STEP 1. M.U.T.-III diagnosis code. |
Check if diagnosis code is set to the ETACS-ECU. |
Q.
Is the diagnosis code set?
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Diagnose the ETACS-ECU. Refer to GROUP 54A, Diagnosis . |
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Go to Step 2. |
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STEP 2. Horn relay check |
Refer to . |
Q.
Is the check result normal?
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Go to Step 3. |
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Replace the horn relay. |
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STEP 3. Voltage measurement at the horn relay connector |
(1)Remove the relay, and measure at the relay box side. |
(2)Measure the voltage between the horn relay connector (power supply terminal) and the body earth. OK: System voltage |
Q.
Is the check result normal?
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Go to Step 5 |
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Go to Step 4 |
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STEP 4. Check of open circuit in power supply line between the fusible link and horn relay connector. |
Q.
Is the check result normal?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to use Troubleshooting/inspection Service Points - How to Cope with Intermittent Malfunction ). |
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Repair the connector(s) or wiring harness. |
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STEP 5. Check of open circuit in N.HO line between the horn relay connector and ETACS-ECU connector. |
Q.
Is the check result normal?
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Go to Step 6. |
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Repair the connector(s) or wiring harness. |
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STEP 6. Check of open circuit in power supply line between the horn (HI) or (LO) connector and horn relay connector. |
Q.
Is the check result normal?
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Go to Step 7. |
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Repair the connector(s) or wiring harness. |
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STEP 7. Horn (HI) or (LO) check |
Connect the battery as shown, and verify that the horn sounds.Q.
Is the check result normal?Go to Step 8.Replace the horn (HI) or (LO). go to step 8. |
STEP 8. Retest the security alarm system. |
Q.
Does the theft-alarm system work normally?
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The trouble can be an intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent Malfunction ). |
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Replace the ETACS-ECU. |
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