Many times ground circuits are not considered when diagnosing electrical issues on your car. We often start with the power feeds and don't look at the grounds yet, bad ground circuits are a critical part of the electrical system. The ground circuits in the ECM / PCM can cause many issues when sensor circuits read incorrectly.

In this video, I walk through how to look at the circuit diagrams and find the grounding points. Many of the GM engines in rear wheel drive applications have engine harness grounds attached to studs at the back of the cylinder heads. These studs are hard to see and reach, yet are critical points in the ground paths for the engine controls and other circuits.

DISCLAIMER: In my videos and written or text comments, I provide demonstrations, suggestions, and opinions on techniques, methods, and materials for various projects. While I try to be accurate, there are no guarantees, expressed or implied, that my information is correct and will work for you. If you wish to use any of this information, you must check and verify that it is appropriate for your use - use it at your risk. Do-it-yourself projects are variable and there are risks in conducting them.