The manual says, warm up the motor and then start the engine with the A and B links shorted and it should idle at about 1100 rpm to show Diagnostic mode is activated.

Mine doesn't idle any faster than it usually does.

Anyone figured out which bit has failed in these cases?

Is the ECU repairable?

I checked out my ISC solenoid and its seems OK, so what next?

Admiral Duck EF Fairmont - tows the boat real well.