engine speeds up

[63shult]

i have 04 dodge 3500 the engine revs buy it self when it is cold out like in the winter check the codes p2121 p2123 where is the pedal position sensor? any help appreciate thanks

 

[TCDiesel]

Need More Info... .

 

[JMarketos]

I know the 05's have an auto idle-up feature. If it detects cold engine and trans in park and idling for something like more than a minute, while the outside temp is below some value, it will idle itself up to around 1100 RPM to aid in warmup. I wouldn't be surprised if this "feature" existed in other model years also.

 

[JJPage]

When the ambient temperature drops, the high idle feature is automatic, usually to about 1100 rpm. Not sure at what temp this happens, but mine seems to do it around 30*F and lower.



What transmission do you have? If it's an Auto, your APPS(accelerator pedal positioning sensor) should be mounted on the engine's left(driver) side, high up towards the front, under a black plastic shroud.

 

[mrtrombley]

That's exactly what mine does when cold out. After about a minute it idles up to about 1100 rpm and pretty much stays there until I take it out of park to move.

 

[63shult]

it is automatic the cruise does work and t/c stays in lock up the engine speeding happen after it is warm up like at traffic light and it also has a dead pedal i have been doing some research on internet and looks like a problem with apps

 

[jelag]

JJPage is correct... . I have 3 of these truck and each of them have a high idle when its cold out... . they all do it differently based on the software in the ECM but the theory is that at idle the engine will not stay at operating temperature for the truck to meet idle emissions... so the engineers have built in a fast idle to warm the engine and make it meet emission standards for the year built... .

 

[JJPage]

Here is a link for a new APPS, it is better than the factory unit, and much more reasonably priced(160. 00).

Timbo APPS

 

[Blakers]

Mine has done it since it was new. Jumps up to about a 1000 rpm. Sometimes it will drop back down after a while. Even when the truck has been run all day it does it - probably some emissions junk. I wish I could get it to stop doing it as it drives me crazy when I'm working outside the truck and trying to listen to the radio.

 

[AH64ID]

The feature most of you are describing is the automatic idle-up programmed into the ECM. It will ramp the rpms up to 1,000 after 2 minutes of stationary time if the ambient temp is below ~32, the intake air temp is below 66*, and the coolant is below 200*. This has nothing to do with emissions, but rather to keep cylinder temps up and allow for complete combustion. This will help keep the motor warm and reduce wet stacking, where un-burt fuel can damage your cylinder walls. Also when you first start the truck below ~15* the rpms will go to 1,000 instantly.

This sounds nothing like what the OP is describing. The auto idle up will not create codes or a deal pedal issue. I agree with the APPS diagnosis.

 

[63shult]

thanks the information guys i am going to order a new APPS

 

[63shult]

i replace the APPS from Timbos APPS truck runs fine

 

[AH64ID]

Always nice when a plan comes togeher! Glad to hear it worked for you.