Emissions Codes have been thrown... '96XJ

Okay,
I tried searching for this combination and for the code numbers and nothing seemed to quench my confusion. My check engine light came on last Friday. I had it scanned yesterday and the following was discovered:

Code P1491: Manufacturer Control Auxiliary Emission Controls
Code P0443: Emission Control System Purge Valve C Fault
Code P0505: Idle Control System Malfunction

1996 XJ, base/sport model, 4.0L, AW4, 4x4, 148k miles

Now the truck seems to run fine expect a slightly stumbling idle – very slight. It doesn’t seem to be using anymore gas than normal either. The dude at the parts store (I know they’re sometimes idiots) said he would look first at the cat. I’m fairly certain it’s not the cat as the truck still takes off like a bandit form a stop and never seems to “choke” or not be able to breathe.

Any ideas will be investigated. I’m only online at work so I can’t check back too often but I do check a couple of times a day. Thanks for the help.
HighTop

One thing comes to mind for me and that's a bad vacume line(s). There's a little thing on the passanger side of the firewall that kind of goes thunk thunk at idel and has vacume lines running to it along with some wires. I think it's for the fuel tank vent/charcoal cannister thing.

JoBo

I saw that canister. It has three ports on top but I only have two lines coming off of it. The one furtherest from the engine has nothing attached to it but I haven't been messing around with it so I figured it was blanked off or something. I quickly looked around and I didn't notice any loose lines hanging into space. I guess I'll look closer this afternoon. I thought it was odd that one of the ports was unoccupied but since I hadn't touched I dismissed it. Thanks JoBo.

Remove the MAP sensor, Idle air controller motor, and Throttle position sensor, and then remove the throttle body. Buy a can of throttle body cleaner and use the entire can on it. Make sure you spray in the cavity for the IAC until the TB cleaner runs clean on the exit side. Clean off the rod on the IAC motor using the same method. You may want to use a toothbrush on both, it helped on mine. Be careful you do not get anything wet on the sensors. This may help with the P0505 code.

The auxiliary emissions control makes me think downstream O2 sensor but that's just a guess.

Check google for a list of codes. I saw one somewhere but can't find it now.

You could try to get the codes using the key on-off method but it wouldn't work for me. I do have a list of those codes.

www.allpar.com/fix/80s-codes.html

www.go.jeep-xj.info/HowtoECUcodes.htm

HTH

Dirk,
Great info and very helpful sites. On the topic of the O2 sensor, wouldn't it have it's own code? I don't know I'm just supposing, my OBD-1 vehicles have had a particluar code for the O2 sensor. It seems that OBD-2 would have one or two codes for the sensors.

I'll try the key method for the codes just to verify what the dude gave me - if it works.

By the way, nice butt

HighTop