My God Jagboy64, you certainly did a great job enlightening me about this. I will send your text to the dealership mechanic I found and see if he can help me now.
Thanks very much,
BuzGuy a/k/a Guy Giordano

 

Hey, was late getting back from my trip but checked that today...

On my 1995 model it doesn't even show results for the ABS system at all, says it's a "non-interactive module".

However, on my 1996 model it shows the ABS and says there are no codes stored for the ABS system (which there should not be on my car).

 

I learned something on my trip about the IACV module. I stopped and visited a friend who's very very experienced and has several Jags including some with AJ16 engines and I told him about my idle issue. Which mine is fixed.

However, I was telling him about some others who still have problems, and he said one common problem is the IACV gets "out of sync" with the computer for some reason and some people think only a dealer can reset it. He said actually the IACV works by simply turning a shaft that has threads, it moves the "head" up and down. He said if your IACV is working (moving the head up and down like when you cycle the key) but is out of sync you can manually move it back close to sync. You take it out and you manually screw the "head" out a bit further.

You want to do a couple of power cycles on the key (a procedure mentioned earlier in this thread) which will get it to it's most extended position, but if that position is still allowing too much air past you can turn the car off, unplug the IACV, and then remove it and manually turn the head to move it so it is further extended. If you have already cycled the key so it's in what the computer thinks is the furthest position out and that's not enough then you turn it so when you sit it into the hole with the gasket and O-Ring in place that the head just barely tries to hold it from seating fully (just a very slight gap around the gasket) but that you can still easily (and with virtually no pressure) push it down so it seats fully (no gap around gasket). If you screw it out too far it will be hard to press down and even though the screws will pull it down it would be jammed from being too tight. So what your looking for is for it to be very lightly seated once it's fully screwed down. Then re-plug the connector and turn on the key without starting the car, wait 10 seconds, turn the key off, wait 10 seconds, and then start the car. This has now moved the "head" of the IACV so it's more extended allowing less air through, your just manually moving the IACV so it now really matches up with the position the computer thinks it's in. Run it a bit and then if needed (and if you have one) use the idle air bypass screw to fine-tune your idle.

He said sometimes the reason they get out of sync is the computer tells it to turn but the shaft has gotten dry and is dragging so the computer said turn 5 times but due to drag it only turned 4 before the power cut off. The module doesn't "count" turns but merely runs the amount of times that SHOULD have made it rotate 5 times. Sometimes if it is stiff you may have to GENTLY use a pair of pliers to grip it to break it loose before you can adjust it. He said one of the biggest causes of them to fail is that they simply got dirty and are not moving freely as they get old and often you can screw the head completely off the shaft (watch for the spring and don't loose it) and lightly brush the threads with a light coat of white lithium grease and they will start working again just fine.

He said he's fixed several of his this way over the years.