1990 Graduate Computer Code 1223. Help please.

[kjd186]

I have a check engine light problem with an erratic throttle idle at times. The code is showing 1223. I believe the throttle position sensor is bad. When I disconnect the sensor when the erratic idle happens, I don't realize much change in the erratic idle. Does anyone know what code 1223 is or any ideas on what could be the problem? Thanks for the help.

[MrT]

From http://www.digest.net/alfa/FAQ/164/diag.htm

"1-2-2-3
The heated lambda probe regulator inner adjuster reaches the minimum
or the maximum value of correction."

Essentially, the mixture is out of spec either rich or lean. My limited experience is that this indicates an air leak (unmetered air) and the AFM signal results in too little fuel. The O2 sensor (lambda sensor) reads lean exhaust and can't correct within the limited range it is allowed to monkey with things. Of course, it might also mean the lambda sensor is bad. Hook a voltmeter up to the lambda probe (pics on the alfabb somewhere) and squirt some hydrocarbons into the intake and see whether the engine smooths out and the signal comes up. If so, then you are lean. If the signal comes up and the engine sags further, then it may be over-rich already because the lambda probe is lying and needs to be replaced.

Michael