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 | -- |
Hood Closed Switch Signal | 1 | 1 | 1 | -- |
Ground | -- | 1 | -- | -- |
1. Hood ajar switch malfunction | ||||
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.
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
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
- Ignition OFF, disconnect the harness connector at the hood ajar switch.
- Ignition OFF, test for less than 5 ohms between the ground circuit terminal C and ground.
- Ignition ON, test for 11.5-12.0 volts between the signal circuit terminal A and ground.
- Ignition ON, test for 11.5-12.0 volts between the signal circuit terminal B and ground.
- If all circuits test normal, test or replace the hood ajar switch.
| ⇒ | If greater than the specified range, test the ground circuit for an open/high resistance. |
| ⇒ | 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. |
| ⇒ | 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. |
Component Testing
Hood Ajar Switch
- Ignition OFF, disconnect the harness connector at the hood ajar switch.
- With the switch in the hood closed position, test for infinite resistance between the ground terminal C and the signal terminal A.
- Test for less than 2 ohms between the ground terminal C and the signal terminal B.
- With the switch in the hood open position, test for infinite resistance between the ground terminal C and the signal terminal B.
- Test for less than 2 ohms between the ground terminal C and the signal terminal A.
| ⇒ | If not infinite, replace the hood ajar switch. |
| ⇒ | If greater than the specified range, replace the hood ajar switch. |
| ⇒ | If not infinite, replace the hood ajar switch. |
| ⇒ | If greater than the specified range, replace the hood ajar switch. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for BCM or instrument cluster replacement, programming and setup |
