Built-in diagnostic service mode?

Anyone tried to access the built-in diagnostic service mode as outline in the "Maintaing the GM Northstar Engine" article located at here? (http://www.babcox.com/editorial/us/us100232.htm?)

It reads:

To enter the built-in diagnostic service mode, press the OFF and WARMER buttons simultaneously and hold until all the segments on the display panel light up. If there are any engine or other trouble codes in memory, they will be displayed.

I've tried it on my '95 and only get an increase / decrease in the temp...no codes.

Anyone else?

Dave

It only works on the Cadillac Northstars,not the Aurora Northstar.

BKVic