[NickD]

Least it explains why CHIEFZUSAF TSC lamps came on with vacuum leak problems.

This is something that still amazes when bread boarding a new circuit design, the circuit itself knows if you followed all natural laws in the design. If not, will burn up in your face.

Not true with software, can lie like crazy and still get away with murder. And nothing will burn up in your face.

 

[NickD]

With a vehicle like my old OBD I 92 DeVille or 88 Supra, any error code can be displayed on the IP, came from the factory this way. Just needed a list to explain what those codes meant. When switched to OBD II, was laying out 5,600 bucks for a GMtech II scanner that did essentially the same thing.

The check engine lamp is one big fat "OR" gate that outputs a logical "1" for any of a several hundred different codes. Don't know if your EGR valve is burning up your engine or your gas cap is loose.

My point is, that can also use that logical "1" to disable the TCS, and apparently this is what they elected to do. But don't ask me why!

One reason why I call the CEL a HAL from that odyssey movie, But stands for a Heart Attack Lamp!