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 | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Hood Ajar Switch Signal | 1 | 1 | 1 | -- |
Ground | -- | 1 | 1 | -- |
1. Hood ajar indicator/message malfunction; Remote vehicle start inoperative | ||||
Circuit/System Description
The hood ajar switch is part of the hood latch and uses two resistors to determine the state of the hood. The body control module (BCM) apply a reference voltage on the hood ajar switch signal circuit. With the hood closed, the hood ajar switch opens and the hood ajar switch signal circuit is grounded through a 750 ohm and a 6K ohms resistor in series. When the hood is opened, the hood ajar switch closes and the hood ajar switch signal circuit is from ground through only the 750 ohm resistor. The BCM then sends a serial data message indicating the status of the hood to the instrument panel cluster (IPC), which will illuminate or displays the hood ajar indicator indicator/message as appropriate.
Reference Information
Schematic Reference
Connector End View Reference
Description and Operation
Keyless Entry System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
- Hood closed, verify the scan tool BCM Hood Ajar Switch parameter is Closed.
- Hood open, verify the scan tool BCM Hood Ajar Switch parameter is Open.
Circuit/System Testing
- Ignition OFF, disconnect the harness connector at the hood ajar switch.
- Test for less than 10 ohms between the ground circuit terminal B and ground.
- Connect the harness connector at the hood ajar switch. Disconnect the X1 harness connector at the BCM.
- Ignition ON, verify a test lamp does not illuminate between the signal circuit terminal 26 and ground.
- Ignition OFF, hood closed, test for 700-800 ohms between the signal circuit terminal 26 and ground.
- Hood open, test for 6K-8K ohms between the signal circuit terminal 26 and ground.
- If all circuits test normal, replace the BCM.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | If the test lamp illuminates, test the signal circuit for a short to voltage. |
| ⇒ | If not within the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the hood ajar switch. |
| ⇒ | If not within the specified range, test or replace the hood ajar switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM replacement, setup, and programming |
