Doors, Hood and Trunk: Testing and Inspection

Hood Ajar Indicator/Message Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* 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) applies B+ to the hood ajar signal circuit and monitors the voltage to determine the position of the hood. The hood ajar switch contains a multiplexed resistor. This resistor will vary the voltage seen by the BCM by pulling down the applied voltage based on the position of the switch.

Reference Information
Schematic Reference

Immobilizer Schematics
Connector End View Reference

Component Connector End Views
Description and Operation

Keyless Entry System Description and Operation
Electrical Information Reference

* Circuit Testing
* Connector Repairs
* Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool BCM Hood Ajar Switch parameter. With the hood open, the Hood Ajar Switch parameter should be Open. With the hood closed, the Hood Ajar Switch parameter should be Closed.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B55 hood ajar switch.
2. Ignition OFF, test for less than 10 ohm 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 B+ between the signal circuit terminal B and ground

• If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 BCM.

4. Ignition OFF, disconnect the harness connector X4 at the K9 BCM.
5. Ignition ON, test for less than 1 V between the signal circuit terminal C and ground.

• If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K9 BCM.

6. If all circuits test normal, test or replace the B55 hood ajar switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

* Hood Primary and Secondary Latch Replacement
* Control Module References for BCM replacement, programming and setup