Hood Ajar Indicator/Message Malfunction

Hood Ajar Indicator/Message Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The body control module (BCM) monitors the voltage input of the hood open switch signal circuit and the hood open closed switch signal circuit. With the hood open, the hood ajar portion of the switch is closed, grounding the hood ajar switch signal circuit from the BCM, and the hood closed portion of the switch is open. With the hood closed, the hood closed portion of the switch is closed, grounding the hood closed switch signal circuit from the BCM, and the hood ajar portion of the switch is open. During proper operation, the two separate voltage signals at the BCM should never be at the same voltage.

Circuit/System Verification

Ignition ON, observe the scan tool BCM Hood Open Switch and Hood Closed Switch parameters. With the hood open, the Hood Open Switch parameter should read Active and the Hood Closed Switch parameter should read Inactive. With the hood closed, the Hood Open Switch parameter should read Inactive and the Hood Closed Switch parameter should read Active.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the hood ajar switch.
2. Ignition OFF, test for less than 5 ohms of resistance between the ground circuit terminal C and ground.

• If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, test for 11.5-12.0 volts between the signal circuit terminal A and ground.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

4. Ignition ON, test for 11.5-12.0 volts between the signal circuit terminal B and ground.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the BCM.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.

5. If all circuits test normal, test or replace the hood ajar switch.

Component Testing

Hood Ajar Switch

1. Ignition OFF, disconnect the harness connector at the hood ajar switch.
2. With the switch in the hood closed position, test for infinite resistance between the ground terminal C and the signal terminal A.

• If not infinite, replace the hood ajar switch.

3. Test for less than 2 ohms of resistance between the ground terminal C and the signal terminal B.

• If greater than the specified range, replace the hood ajar switch.

4. With the switch in the hood open position, test for infinite resistance between the ground terminal C and the signal terminal B.

• If not infinite, replace the hood ajar switch.

5. Test for less than 2 ohms of resistance between the ground terminal C and the signal terminal A.

• If greater than the specified range, replace the hood ajar switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

* Hood Primary and Secondary Latch Replacement