HELP 1993 FREIGHTLINER SERIES 60 SHUTS DOWN AFTER 30 SECONDS

No but I thank faults that shut the engine down flash red but even if it is yellow record them. Do you know how to read flash codes? Then search them in the top right search block and or on line.

 

The protection circuit is a 5 pin connector in my 2000 Volvo. Just a plug that goes to a plastic device that is zip tied to an electrical bundle. I had a corroded pin inside the plug. This protector circuit was showing low/high/shorted voltage at coolant level sensor. A shop charged me a fortune to troubleshoot it to a corroded terminal. All they did was to clean it and plug it back in. I took the terminal out and replaced with a new terminal that I purchased from a freightliner dealer. I took the pin in to match it up. I put electrical grease on the connection and plugged it back up. Worked for a long time. I could pull up diagnostic info on the dash of my Volvo. My protection circuit was zip tied to an electrical bundle right next to the steering shaft under the hood very close to the firewall.

 

You can disconnect batteries but if the fault is active it will come right back when you start the engine. Check the jumper to see if it is still in place. If it does not see the sensor it will keep you in derate mode also. If no voltage or shorted it will shut you down after 30 seconds