Pinpoint Test B: The Alarm System Does Not Activate When The Hood Is Opened

Anti-Theft

Pinpoint Tests

Pinpoint Test B: The Alarm System Does Not Activate When The Hood Is Opened

Refer to Wiring Diagram Set 117, Remote Keyless Entry and Alarm for schematic and connector information. Diagrams By Number

Normal Operation - Vehicles With Integrated Keyhead Transmitter (IKT)

When the alarm system is armed, the Smart Junction Box (SJB) monitors the hood ajar switch. If the hood is opened while the alarm is armed, the hood ajar switch removes ground from the signal circuit. This signals the SJB that an unauthorized intrusion to the engine compartment has occurred and the SJB activates the alarm.

Vehicles With Intelligent Access (IA)

When the alarm system is armed, the Remote Function Actuator (RFA) module monitors the hood ajar switch. If the hood is opened while the alarm is armed, the hood ajar switch removes ground from the signal circuit. This signals the RFA module that an unauthorized intrusion to the engine compartment has occurred and the RFA module activates the alarm.

- DTC B1520 (Hood Switch Circuit Open) - set by the SJB if it detects an open in the hood switch circuit during the self-test.
- DTC P254F:13 (Engine Hood Switch Circuit / Open: Circuit Open) - set by the RFA module if it detects an open in the hood switch circuit during the self-test.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors
- Hood switch
- SJB (vehicles with IKT)
- RFA module (vehicles with IA)



PINPOINT TEST B: THE ALARM SYSTEM DOES NOT ACTIVATE WHEN THE HOOD IS OPENED

NOTICE: Use the correct probe adapter(s) when making measurements. Failure to use the correct probe adapter(s) may damage the connector.

NOTE: Failure to disconnect the battery when instructed will result in false resistance readings. Refer to Battery.

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B1 CHECK THE HOOD SWITCH


- Ignition OFF.
- Disconnect: Hood Switch C127.
- Measure the resistance between the hood switch C127 pin 1, component side and the hood switch C127 pin 2, component side while pressing and releasing the hood switch plunger.




- Is the resistance less than 5 ohms with the hood switch plunger pressed, and greater than 10,000 ohms with the hood switch plunger released?

Yes
GO to B2.

No
INSTALL a new hood switch. TEST the system for normal operation.

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B2 CHECK THE HOOD SWITCH SIGNAL CIRCUIT FOR AN OPEN OR SHORT TO GROUND


- Disconnect: SJB C2280f (Vehicles With IKT).
- Disconnect: RFA Module C2153e (Vehicles With IA).
- For vehicles with IKT, measure the resistance between the SJB
C2280f-10, circuit CPL25 (BU/OG), harness side and the hood switch C127-1, circuit CPL25 (BU/OG), harness side; and between the SJB C2280f-10, circuit CPL25 (BU/OG), harness side and ground.




- For vehicles with IA, measure the resistance between the RFA module
C2153e-23, circuit CPL25 (BU/OG), harness side and the hood switch C127-1, circuit CPL25 (BU/OG), harness side; and between the RFA module C2153e-23, circuit CPL25 (BU/OG), harness side and ground.




- Is the resistance less than 5 ohms between the SJB (or RFA module) and the hood switch, and greater than 10,000 ohms between the SJB (or RFA module) and ground?

Yes
GO to B3.

No
REPAIR the circuit. TEST the system for normal operation.

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B3 CHECK THE HOOD SWITCH GROUND CIRCUIT FOR CONTINUITY


- Disconnect: Negative Battery Cable.
- Measure the resistance between the hood switch C127-2, circuit GD123 (BK/GY), harness side and ground.




- Is the resistance less than 5 ohms?

Yes
For vehicles with IKT, GO to B4.

For vehicles with IA, GO to B5.

No
REPAIR the circuit. TEST the system for normal operation.

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B4 CHECK FOR CORRECT SJB OPERATION


- Connect: Hood Switch C127.
- Connect: Negative Battery Cable.
- Disconnect all the SJB connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the SJB 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 SJB. REFER to Body Control Systems. 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.

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B5 CHECK FOR CORRECT RFA MODULE OPERATION


- Connect: Hood Switch C127.
- Connect: Negative Battery Cable.
- Disconnect all the RFA module connectors.
- Check for:
- corrosion
- damaged pins
- pushed-out pins
- Connect all the RFA 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 RFA module. REFER to Body Control Systems. 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.

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