Volt L4-1.4L Elect (2011)
The hybrid powertrain control module 2 applies B+ to the hood ajar signal 2 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 hybrid powertrain control module 2 by pulling down the
applied voltage based on the position of the switch.
Conditions for Running the DTC
Propulsion system is active.
Conditions for Setting the DTC
P257D
The hood ajar switch signal 2 voltage as measured by the hybrid powertrain control module 2 is not within a valid voltage range.
P257E
The hybrid powertrain control module 2 detects a short to ground in the hood ajar signal input to the hybrid powertrain control module 2.
P257F
The hybrid powertrain control module 2 detects a short to voltage or an open/high resistance in the hood ajar signal input to the hybrid powertrain
control module 2.
Action Taken When the DTC Sets
The engine will start and run whenever the ignition is ON and the vehicle speed is less than 5 kph (3 mph).
Conditions for Clearing the DTC
DTCs P257D, P257E, and P257F are Type B DTCs.
Reference Information
Schematic Reference
Immobilizer Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
Hood Ajar Indicator Description and Operation (See: Body and Frame/Doors, Hood and Trunk/Description and Operation)
Electrical Information Reference
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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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 be Open. With the hood
closed, the Hood Position 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 5 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, verify DTC P257F is set as current.
