Howdy guys, Paps truck is down and I'm currently 1600 Miles from either him or the truck.  So we could use y'alls assistance.

 

Rig specs: 1999 Dodge 3500 NV4500 4x4 with 3 year old Timbos APPS

 

Truck was running fine, then it started to high idle on startup to about 1100 RPM (He doesn't have a high idle kit)  no delay, it just went straight to 1100.  Then a day or two later he started it up to find it also had dead pedal stuck at 1100RPM (in a Walmart parking lot lol (Thank heavens for Torque!!!))

 

He did some research on the issue, and decided to try and reset the apps doing the 30 minute battery disconnect thing and then pumping the throttle slowly.  Apparently that fixed the issue for a couple days, but now it's high idling again (didn't check for dead pedal).

 

So what are all y'alls thoughts?  

 

If the APPS was bad, I'm a little confused as two why a reset would fix it.

Last I spoke with him there was no check engine light.  I forget if he checked codes or not.

 

My current thoughts are to see if he can unplug the apps and see if that will make it idle.  And then do a visual check to make sure everything is installed as it should be and the apps isn't dangling or something.

Next would be checking the APPS voltage and Idle validation switch (Anyone got a good link to what it's suppose to be at?).  Though I'm not sure if this is an option due to his limited tools out there.

 

Thanks guys!

Edited April 13, 20178 yr by Cowboy

AC noise issue coming on. The need for APPS reset and then getting relief for a short time points to AC noise from the alternator driving the ECM nuts. Now if the second time does the same he need to test for AC noise and replace the alternator first thing. 

Thanks Mike!  I let him know.  We'll see how this second reset works out.

He replaced the alternator with a parts store one, but did have them check it before installing.  I know, not ideal, but options are kinda limited when you're on the road.  So far so good, dead pedal hasn't come back, and he said his mileage has gone up as well.

 

He mentioned that he's been having a problem with the grids cycling when the engine's hot, it's been doing this for almost a month.  Like if you park it for 20 minutes and start it back up, it will cycle the grids.  He already replaced the intake temp sensor, and he said his overhead console and engine coolant temp appear to be reading correctly.  Any ideas?  I'm kinda of the mind that the alternator scrambled the PCM in the same way it did for the APPS.  Is there any way of resetting it other than bringing it to a dealer to be re-flashed?  Thanks again!

7 hours ago, Cowboy said:

He mentioned that he's been having a problem with the grids cycling when the engine's hot

 

This is normal if the outside temperature is below 60*F. The other sensor that kicks in is the battery temperature sensor. Like on my truck if I use MPG mode which is 143*F IAT temp so now outside temperature is below 60*F the grid heater will still cycle post starting.  

Yep, it'll do it with the engine hot at 80°F.  I totally forgot about the battery temp sensor.  I'll have him test it and see what happens.  Thanks again!