2019 Dodge Durango Hood Ajar Warning & Start/Stop Disabled: Diagnosis and Repair

Initial Diagnosis and Customer Complaint

• 💡 The vehicle, a 2019 Dodge Durango with 92,000 miles, presented with a persistent "hood open" warning light on the dash and the "start/stop system disabled" message.
• 🎯 The customer had already replaced the hood latch with an OEM part, but the issue persisted, leading them to seek professional diagnosis.

Diagnostic Scan and Code Analysis

• 🔍 A scan tool was connected, revealing codes P257F ("hood engine hood switch circuit high") and B181E13 ("hood ajar input circuit open") in the Body Control Module (BCM) and Powertrain Control Module (ECM).
• ⚠️ Service data indicated two hood switches: Hood Switch 1 wired to the BCM and Hood Switch 2 wired to the PCM, both of which could disable the start/stop system if faulty.
• 📊 Initial scan tool readings showed Hood Switch 1 with 2.84 volts when open and 0 volts when closed, while Hood Switch 2 showed no change when its corresponding switch was actuated.

Identifying the Faulty Circuit

• 🔬 Further investigation into service data suggested Hood Switch 1 (the hood ajar switch) was the likely culprit, with a 1000-ohm resistance when open and 500 ohms when closed.
• ⚡ Testing the purple wire with a blue stripe (identified as the voltage reference for Hood Switch 1) revealed only 0.38 volts, indicating a loss of power supply.
• 🔌 The ground side of the circuit tested stable at 0.006 volts, confirming the issue was with the power feed to the switch.

Locating and Repairing the Damaged Harness

• 📍 The harness connector (X8120A) for the hood ajar switch was difficult to locate due to missing information in service data, but was eventually found behind the front bumper cover, indicating it was affected by prior collision repair.
• ⚠️ A visual inspection revealed chafed wires within the harness, with a noticeable green tinge indicating corrosion due to moisture ingress.
• 🛠️ Five wires in the harness were found to be damaged down to bare copper and were repaired using open barrel connectors and marine-grade heat shrink.

Verification and Final Steps

• ✅ After repairing the harness and reconnecting the switch, the hood ajar warning light disappeared, and the start/stop system became available.
• 🧹 A quick erase of codes was performed, and a final scan confirmed the hood latch code was gone, with only a persistent wiper-related code remaining (which was not a customer complaint).
• 🚗 The harness was secured to prevent further rubbing against the support bar, and the fender liner was reinstalled.