Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Theory Of Operation
The Powertrain Control Module (PCM) monitors the hood ajar status of both hood ajar switches on Plug-in Hybrid Electric Vehicles (PHEV) and Electronic Stop/Start (ESS) equipped vehicles for proper operation. Hood Ajar Switch 1 is hard-wired to the Body Control Module (BCM). The signal is sent to the PCM over the CAN Bus. Hood Ajar Switch 2 is hard-wired to the PCM. If the PCM detects that either switch is in the open position or is faulted for any reason during a normal drive cycle, ESS will be disabled for the remainder of the drive cycle. This condition will cause the engine to default to a running state on both PHEV and ESS equipped vehicles. If Hood Ajar Switch 2 is faulted or in the open state it will also cause the Remote Start feature to be inoperative.
For additional information on the effect of this DTC to the operation of ESS, proceed to the ENGINE START/STOP (ESS) INOPERATIVE. . Refer to STOP/START SYSTEM DIAGNOSIS-ESS EQUIPPED .
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.