CEL came on with a P0122 & P0004

[jakewire]

any suggestions where to start looking?

Thanks,
Jake

 

[offrovering]

p0122 is TPS, throttle position sensor. try reseating the connection after cleaning, check for bad wires to the sensor. if it keeps coming back you may need a new TPS.

p0004, i don't know off top of my head, dont have manual around either.

Have you cleared the codes and waited to see if they pop back up? I would try that, always do, clear, drive and see if they pop back up, sometimes an electrical glitch pops up and clears itself.

 

[jakewire]

Followup: I started the jeep and pulled the IAC wire off while it was running. The jeep stalled and then I reconnected it and cleared the codes. When I started it back up the idle was back to normal. It had to be something with the IAC but when I look at my manual the 04 libby has the IAC incased somehow in the throttle body and not connected by two screws like the manual says. Anyone familiar with how to take off the IAC on an 04?

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Reseated it and it didn't help so I installed a new one. Took it for a ride and didn't get any codes but the idle is high. In park it is around 900 and will jump up to 1100 then go back down to 900 and keep doing that.

Could it be the IAC (idle air control)?

I is puzzled!

Jake

 

[Dave]

Idle should be around 650rpm. I don't see a code p0004 listed??

Dave

 

[hyde]

I have the same problem, it idles oddly sometimes. It is generally between 900 and 1100 now. Before it has always been around 6-700. When I shift from Park to Neutral idle changes, back to drive it moves up and down a little. It generally didn't have that much variation. I also reported getting P0122 error recently.

 

[JeepJeepster]

thats b/c you floor your Jeep everyday hyedipin.. Its keeping the rpms higher to get ready for that sudden flooring! haha, jk.

jakewire, Im confused as to why you are unplugging the IAC with the Jeep running(not good) and why you replaced the IAC when the code is calling for the TPS??? If the idle is high after you replaced the IAC, check to make sure you dont have any leaks or vacuum leaks. Did you clean the intake? Is it dirty? Have you check the voltages of the TPS?

 

[tjkj2002]

OBDII code P0004 is "fuel volume regulator control circuit high".

You need to fix the lowest # code first,and in turn it should,not always,fix the other codes of the same nature.


The regulator is part of the fuel pump inside of the gas tank.Since your idle is high and moves sounds like the pressure regulator is not working and allowing very high fuel pressure in which the IAC cannot control.

 

[jakewire]

jakewire, Im confused as to why you are unplugging the IAC with the Jeep running(not good) and why you replaced the IAC when the code is calling for the TPS??? If the idle is high after you replaced the IAC, check to make sure you dont have any leaks or vacuum leaks. Did you clean the intake? Is it dirty? Have you check the voltages of the TPS?

I poorly edited the wrong post.

I replaced the TPS not the IAC.

After replacing the TPS I drove it and didn't get any new codes but the idle was high. With no codes the only thing I could think of was that the IAC was faulty or it needed reset. A quick google search found if you're stuck in a high idle pull the IAC connector to get it to reset.

I am going to replace the IAC just for the heck of it since it isn't an expensive part and for peace of mind..... that is when I figure out how to replace it.

The CD manual and parts fiche say the IAC is held on by 2 screws but I don't see any screws. In my 04 it looks like it is incased somehow that it needs a quarter turn or something to get it out but I need to find a confirmation on that before trying to replace it.

 

[offrovering]

there should be two screws on the "wings" of the IAC. If you don't see those maybe it has been replaced, and the screws werent put back in. it is located on the throttle body neck.

I would try cleaning the area before replacing, but it sounds like the CEL is off, now you are chasing a high idle.

 

[jakewire]

there should be two screws on the "wings" of the IAC. If you don't see those maybe it has been replaced, and the screws werent put back in. it is located on the throttle body neck.

I don't see any wings.

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[offrovering]

that looks different, I am not familiar with the variations from year to year. have you pulled the electrical connection on that to see how it looks?