P254F
DTC P254F
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.
DTC Descriptor
DTC P254F
- Engine Hood Switch Circuit
Diagnostic Fault Information
Circuit/System Description
The engine control module (ECM) 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 ECM, 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 ECM, and the hood ajar portion of the switch is open. During proper operation, the two separate voltage signals at the ECM should never be at the same voltage.
Conditions for Running the DTC
The ECM continuously monitors for this DTC
Conditions for Setting the DTC
Both the hood open switch signal circuit and the hood closed switch signal circuit are simultaneously in an active or inactive state.
Action Taken When the DTC Sets
Engine starting will be disabled.
Conditions for Clearing the DTC
* A current DTC will clear when the conditions for setting are no longer present.
* A history DTC will clear after 40 malfunction free ignition cycles.
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 ECM Hood Position parameter. With the hood open, the Hood Position parameter should read Open. With the hood closed, the Hood Position parameter should read Closed.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the hood ajar switch.
2. Ignition OFF, test for less than 10 ohms 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 10.0-12.5 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 ECM.
• 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 ECM.
4. Ignition ON, test for 10.0-12.5 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 ECM.
• 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 ECM.
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 2.0 ohms 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 2.0 ohms 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.
* Hood Primary and Secondary Latch Replacement Service and Repair
* Control Module References for ECM replacement, programming and setup