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what could pull a p0122 CEL?

NeoMax

NAXJA Forum User
Location
Detroit
[font=verdana, arial]Hey all continuing problem here. I'm pulling a P0122 "Throttle position sensor input below the acceptable voltage range (shorted low)"

Now I've replaced the TPS sensor already, and cleared the compy. Yet still pull that same code. Now what outside of just the sensor could pull that code? the IAC? CPS? MAP? please any ideas?
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have you taken a volt-meter and tested the voltage at the tps to make sure that the voltage isn't off kilter? I am not sure what the appropriate voltage would be, but im sure that someone on here would know. What year XJ?
 
99XJ, acceptable voltage is .7 at idle and ramping up to like 3.7ish at WOT. ( i believe)

I had my meter out the other day and I just couldnt get anything in there for a reading, any tricks to do this?
 
bump bump bump, i have made two threads on this now and with all the jeep gurus here SOMEONE has to have a good idea of what to do.....but no one will :(
 
Are you on pins and needles? ;)

You should be able to jamb either in from behind. Then, use those as your contact points.

Maybe it's dirty contacts at the ECU?
 
Did you clear the code before hooking up the new sensor? Is this a Mopar replacement or aftermarket ?Some sensors and comps will not talk to each other if not factory replacements.
Wayne
 
alrighty, I jammed to flatened staples in there. Unpluged I'm getting 5v on the outside wire and 4 on the middle. plugged in, i get .7v and it ramps all the way up to 3.8, oook so the tps IS working... sorry if I sound desperate but I have school on monday so it needs to be fixed by then and i'm panicing.

I checked all the wiring to make sure nothing is melted or frayed. sooo either bad or dirty ecu??
 
Wayne Sihler said:
Did you clear the code before hooking up the new sensor? Is this a Mopar replacement or aftermarket ?Some sensors and comps will not talk to each other if not factory replacements.
Wayne
Ya I cleared the code yet I'm still grabbing the same error. And no it was from auto zone. maybe i'll go plug the old sensor in and see if sends correct voltages...
 
There is an adjustment proceedure for the TPS. If you don't set it up, you can easily get an output out of range at idle.

A point of interest. If you put your vehicle info in the thread, it's a lot easier to help you. the adjustment proceedure is different on different years and engines.
 
old_man said:
A point of interest. If you put your vehicle info in the thread, it's a lot easier to help you. the adjustment proceedure is different on different years and engines.
I did :laugh3: it was in my second post. I'm sorry too, I should make a sig with it. I think i'll do that right now :) its a 1999 XJ by the way

I'm really thinking my ecu might be bad...I mean how could it be dirty? I've never offroaded or had water/mud enter the cabin. *sigh* this sucks
 
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bah, I hooked up the old sensor and it turns out its sending the correct voltages and sweeps correctly up to WOT. greeat so now what? what could be pulling that code? I'm at a loss...
 
If you have AIM, I could send you a 00 FSM (40MB). Might help out.
Let me know.
 
Have you check the resistance from the TPS connector of the engine wiring harness to the other end at the PCM? Do this for all three wires. You need to confirm your wiring before going and buying parts. I bet you will find your signal return wire open.
 
bottleworks, how do you mean? check the plug at the tps and at pcm right? I couldnt find it in the Haynes manuel, where is the pcm at?
 
NeoMax said:
hmmm i'm stupid I cant find the pcm...
On the wifes 98 it is forward of the top of the washer fluid fill cap.IIRc it looks like 3 square boxes on the top.On my 96 it is in the same area but has a cover .
Could a vac line be off the manifold ?
Wayne
 
well I'm gonna test the pcm and well check every little wire I can think of that could possibly be burnt/melted or w/e tomorrow... God I hope I can fix this, if its not fixed tomorrow it goes to a (sigh) mechanic on monday..

Is it true that I can bring it to the dealership and for a small fee have them diagnois the problem for me? so i know what to fix? Thanks!! :sunshine:
 
bottleworks I love you :) , I did what you said and it turned out to be a frayed wire...rubbed right through. ahhh it runs perfect now, thanks everyone so much :)
 
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