Pinpoint Test E: No Horn Output During Alarm Activation

Anti-Theft

Pinpoint Test E: No Horn Output During Alarm Activation

Normal Operation

The Body Control Module (BCM) receives voltage for the anti-theft alarm horn from the Battery Junction Box (BJB) fuse 6 (30A). When the perimeter alarm is activated, the BCM (Body Control Module) cycles voltage on and off to the anti-theft horn causing the horn output to cycle in conjunction with the turn signals flashing. The horn is case grounded.

NOTE: The traffic horn does not sound during a perimeter alarm event.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- Anti-theft alarm horn

- BCM (Body Control Module)

PINPOINT TEST E : NO HORN OUTPUT DURING ALARM ACTIVATION

E1 CHECK THE POWER DOOR LOCK OPERATION

- Press the door lock control switch twice.

Do the doors lock and unlock?

Yes
GO to E2.

No
REFER to Doors, Hood and Trunk &/or Locks to diagnose the power door locks.

E2 CHECK FOR VOLTAGE TO THE ANTI-THEFT HORN

- Disconnect: Anti-Theft Alarm Horn C4380.

- Enter the following diagnostic mode on the scan tool: BCM (Body Control Module) DataLogger.

- Measure the voltage between the anti-theft alarm horn C4380-1, circuit CRT02 (GY/VT), harness side and ground while active commanding the BCM (Body Control Module) PID (ANTITHFT_HRN) on.





Is the voltage momentarily greater than 10 volts?

Yes
INSTALL a new anti-theft alarm horn. REFER to Anti-Theft Alarm Horn - 4-Door Sedan 4-Door Sedan or Anti-Theft Alarm Horn - 5-Door Hatchback 5-Door Hatchback.
TEST the system for normal operation.

No
GO to E3.

E3 CHECK THE ANTI-THEFT HORN OUTPUT CIRCUIT FOR AN OPEN OR SHORT TO GROUND

- Ignition OFF.

- Disconnect: BCM (Body Control Module) C2280C.

- Measure the resistance between the anti-theft alarm horn C4380-1, circuit CRT02 (GY/VT), harness side and the BCM (Body Control Module) C2280C-8, circuit CRT02 (GY/VT), harness side; and between the anti-theft alarm horn C4380-1, circuit CRT02 (GY/VT), harness side and ground.





Is the resistance less than 5 ohms between the anti-theft alarm horn and the BCM (Body Control Module), and greater than 10,000 ohms between the anti-theft alarm horn and ground?

Yes
GO to E4.

No
REPAIR circuit CRT02 (GY/VT) for an open or short to ground. TEST the system for normal operation.

E4 CHECK FOR CORRECT BCM (Body Control Module) OPERATION

- Disconnect all the BCM (Body Control Module) connectors.

- Check for:
- corrosion

- damaged pins

- pushed-out pins


- Connect all the BCM (Body Control Module) connectors and make sure they seat correctly.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new BCM (Body Control Module). TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.