Throttle postion sensor?

[snum1fan]

Hello everyone!

New on the forum. Looking for some advice on my moms Altima.

Recently the RPM's have started going crazy when at a stop. They go from right under 1 to right above 2 and bounce in between. About this same time the check engine light came on.

I had a friend pull the codes and all it came up with was a max rev limit (I think).

Me and my friend seem to think this is related to the throttle position sensor. The guy my mom got the car from said they replaced it a couple months before she bought it. I think they may have got a used one from a junk yard or something.

My fried cleared the code but it just comes back on after 5 mins.

Any one have any idea about this?

Any help is greatly appreciated.

Thanks!

[snum1fan]

OK

So the codes it is giving are

P0507 - Idle cntrl system RPM above expected

AND

P0420 - Catalyst efficiency below threshold bank

I turned the CEL off today and I drove it about 15 miles and it did not come back on. Before it would come back on after 5 mins.

Symptom wise when you are stopped and the car is just idling the RPMs jump all over the place. And when you are moving it kinda gives and pulls.

There is a recall out to reprogram the ECM (or ECU?). I am going to have Nissan do that first before I start throwing parts at it.

[TECHLINE08]

What year Altima? There are pently of recalls for the third gen altima. The ECU reprogram recall will not fix the problems you have.

When replacing Throttle postion switch (IAC actuator). You need to relearn idle air volume. Which is easyer to do with a consult. If it is not done you will get a surging idle. And the 507 code will likely be stored. Hope this helps.

[snum1fan]

Hi,

Thanks for your response.

Its a 2002.

So I would assume that the guys who replaced the sensor last time may not have relearned the idle air volume. Maybe I should take it into nissan and see if they can figure it out.

I was trying to avoid that. I guess they would tell me what it needs and if it needs a new sensor I could do that then have them learn it?

[TECHLINE08]

if your sure its been replaced, then just go to a Nissan dealer and tell them that all you need is a idle air volume relearn.

[snum1fan]

I'm pretty sure that it was replaced. If I were to bring it to Nissan and it turned out that it wasnt replaced and needed a new one, do you have any idea on what it would run to have them replace it and program it?

I dont know if I will be able to tell by looking at it but I will take a look again.

Thank You SO SO SO much for your help.

[TECHLINE08]

Probably around $300, 1.5hr install and program, $170 for the actuator. Thats a good guess

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