A 2108 Volkswagon Atlas is stuck in a start stall condition with a fault code P0642 - Sensor Reference Voltage A Circuit Low. We deep dive into wiring diagrams and sensor testing to track it down.
In this service information rich diagnostic video, we tackle a no start condition on a 2018 Volkswagon Atlas. The scan tool reveals fault code P0642 - Sensor Reference Voltage A Circuit Low, and from there, we build a game plan using wiring diagrams, voltage checks, and component isolation.
You'll follow me along as we:
- Analyze VS vs VS5V signal lines in the diagram
-Test 5V reference voltage at multiple sensors
-Systematically unplug cam/crank, MAP, turbo, and intake sensors
-Discover the real cause : a shorted engine temperature control module leaking coolant into its connector
Once we unplug it, the 5V reference comes back and the Atlas roars to life.
If you enjoy real world diagnostics, deep dives into service info, and critical thinking with a lab coat twist - this video is for you.