P254F
DTC P254F
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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 starter/generator control module (SGCM) 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 SGCM, and the hood ajar portion of the switch is open. During proper operation, the two separate voltage signals at the SGCM should never be at the same voltage.
The hood ajar switch status is also sent to the engine control module (ECM) via serial data.
Conditions for Running the DTC
The SGCM 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
Auto-start and auto-stop operation 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 (Immobilizer Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Keyless Entry System Description and Operation (without Accessory 2 Way Remote) (Keyless Entry System Description and Operation (without Accessory 2 Way Remote))Keyless Entry System Description and Operation (with Accessory 2 Way Remote) (Keyless Entry System Description and Operation (with Accessory 2 Way Remote))
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, observe the scan tool SGCM 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 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 SGCM.
• 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 SGCM.
4. 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 SGCM.
• 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 SGCM.
5. Ignition OFF, connect the harness connector at the hood ajar switch.
6. Ignition ON, observe the scan tool SGCM 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.
• If the parameter does not change between the specified values, test or replace the hood ajar switch.
7. 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.
• If the parameter does not change between the specified values, replace the ECM.
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 the specified value, 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 the specified value, 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 (Verification Tests) after completing the diagnostic procedure.
* Hood Primary and Secondary Latch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for ECM or SGCM replacement, setup, and programming