THEFT DETERRENT SYSTEM > Horn Circuit |

| 1.INSPECT HORNS |
Press the horn switch and check if the horns sound.
| Result | Proceed to |
| Horns sound | A |
| Horns do not sound | B |
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| A | |
| 2.PERFORM ACTIVE TEST USING INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the intelligent tester on.
Enter the following menus: Body Electrical / Main Body / Active Test.
According to the display on the tester, perform the Active Test.
| Tester Display | Test Part | Control Range | Diagnostic Note |
| Vehicle Horn | Vehicle horns | ON/OFF | - |
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| OK | ||
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| 3.CHECK HARNESS AND CONNECTOR (INSTRUMENT PANEL JUNCTION BLOCK - INTEGRATION RELAY) |
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Disconnect the 3B instrument panel junction block connector and 1D integration relay connector.
Measure the resistance according to the value(s) in the table below.
| Tester Connection | Condition | Specified Condition |
| 1D-11 - 3B-22*1 | Always | Below 1 Ω |
| 1D-9 - 3B-22*2 | Always | Below 1 Ω |
| 3B-22 - Body ground | Always | 10 kΩ or higher |
| *1 | Front view of wire harness connector (to Integration Relay) |
| *2 | Front view of wire harness connector (to Instrument Panel Junction Block) |
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| OK | |
| 4.REPLACE MAIN BODY ECU |
Temporarily replace the main body ECU with a new or normally functioning one (Click here).
| NEXT | |
| 5.PERFORM ACTIVE TEST USING INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the ignition switch to ON.
Turn the intelligent tester on.
Enter the following menus: Body Electrical / Main Body / Active Test.
According to the display on the tester, perform the Active Test.
| Tester Display | Test Part | Control Range | Diagnostic Note |
| Vehicle Horn | Vehicle horns | ON/OFF | - |
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| OK | ||
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