i got my '01 2500 programmed on saturday for the high idle feature, they had to flash the PCM with the newest software for the high idle to be enabled, no problems with that or the high idle, the problem is that on Sunday i went to the store and the check engine light came on with a P0500 VSS malfunction, im thinking that when the re-flashed the PCM the tire size setting may have changed somehow?

EDIT: after doing some more searching, it appears that some other people have had this code when they have let the truck stay in high idle mode for awhile, i guess i wont worry about it too much, if anyone else has any other ideas i would love to hear them, thanks, Joe

 

Relax...

Simple version and most common...
Here is the diagnostic if you want to double check...
Mopar1973Man's Dodge Cummins Articles - P0500 No Vehicle Speed Sensor Signal

 

From what I have seen, reflashing the ecm can cause the pinion factor to be lost. This happens sometimes but not always. I would check to make sure your tire size data is still valid in the abs module. You may need access to a factory DRB scan tool for this. I have not tried this with my Snap On red brick. Maybe tonight I will go hook up to my truck and see what I can change around.

Just curious, Does your Speedo still work? Do you have ABS and brake lights on? If you had it flashed at the Dealership, I would go back and ask them to see if they can program this data for you.

 

I read your website about the issue, but i have had no wheel spin since the update and it has been working code free for years before the update, which leads me to believe that the PCM is not calibrated correctly, or extended high/3cyl idle may have set it (i let it run a full 3 cyl warm up cycle right before it set the code)

speedo works as it should, no ABS light, P0500 is the only code stored, i am planning on driving it a few days without activating the high idle to try to eliminate that as a possible cause and be more positive that it is the PCM programming before i take it back to the dealer

 

UPDATE:

so ive been driving the truck this week, probably had at least 5-7 drive cycles on it, and without using the high/3cyl idle i had no pending or active codes.

About an hour ago when i got home i hooked up my scan tool, made sure i had no pending codes, then started the truck and set the switches (thanks moparman for the wiring diagram) for 6cyl high idle, within about 2min after it idled up i had P0500 pop up under pending codes so i turned it off, restarted it and ran it up again and after two minutes the pending P0500 went full out active and the check engine light came on, so i guess that i can live with that but IMO its stupid logic in the PCM to set a speed sensor code just because the idle is high

and i tried one more thing, the mysterious PTO wire, I grounded it and got a response from the PCM showing "PTO active" but it did not keep the P0500 code from setting, oh well its not a big deal, but im a little OCD so any light on even if they don't mean much irritate me

 

P0500 is a ABS code (not a PCM or ECM code)

PTO wire only prevents certain codes from occurring while operating a PTO device. The PTO wire doesn't set high idle or throttle operations.

High idle shouldn't have another to do with the P0500 code because the high idle feature is only active if there is 0 MPH and the high idle software is a ECM thing where the P0500 is a ABS thing. Two different systems.

 

P0500 is not an ABS code. The abs module does not show P codes. Did they flash the ECM or PCM or both? The factory diagnostics say to check the ABS module for codes if this code appears in the PCM. If there are codes in the ABS module address those first. If not then proceed to next step which basically says to start checking the wires from the ABS module to the PCM for shorts, resistance etc. My feeling is this. If the problem only occured after the pcm update, then there may be a problem with the update. There may not be anything that you can do and you are at the mercy of the programers at Chrysler.

 

im not sure if they flashed one or both, i can get the info off of the sticker they put on the core support if that will help? AFAIK there are no ABS codes at least active ones, i cant access the abs module with my scan tool so i cant say 100%. My truck is a very base model, crank windows, no tilt, no cruise, or much else other than a/c i wouldn't think that would matter since im pretty sure they use the same PCM/ECM with every trim level truck? I would go back to the dealer, but i really doubt they would be able to do much about it, since the update works like it should other than this little issue.

MoparMan, since i have read that grounding the PTO wire prevented certain codes from appearing i was hoping that it would prevent this one but it did not, i know the high idle should not have anything to do with that code but for some reason on my truck it does!

 

If you can get access to a scan tool with some more capability, there is something else you can try. Relearn Pinion Factor in the ABS. I have seen during reflashes that the pinion factor programing is lost to the PCM even though it was still valid in the ABS module. Typically when the pinion factor is programed it relearns that corisponding modules such as PCM.

 

That's what got me scratchin' my head.

P0500 is basically a speed sensor error. (Movement) But high idle will only function when not moving. So neither one can be related.

Depends how you look at it... Yes. It might be reported on the PCM side but the ABS module trigger the PCM report it. Then if you read over the diagnostics then you see most of it testing the CAB module (Controller Antilock Brakes)

Mopar1973Man's Dodge Cummins Articles - P0500 No Vehicle Speed Sensor Signal

Mopar1973Man's Dodge Cummins Articles - Antilock Braking System (ABS)