Hello, I have a 2000 dodge ram 1500 5.2 magnum automatic
I bought it for 1100 bucks with 128k on it. It had some normal
Issues such as crankshaft position sensor was bad. Needed a new battery
Shocks etc. I had three codes at first and got it down to one the p0505 which
Is the IAC I have put three IAC on the truck checked the wiring checked the vacuum hoses everything. The light will not go off. The truck runs great. It wouldn't idle at first but since the 3rd IAC it starts right up and runs perfect I've disconnected the negative to clear it. Even had a scanner clear it and as soon as I started it up it came back on. Inspections fixing to go out and I need it gone. I have cleaned the throttle body the MAF replaced the TPS new gas cap rear end sensor tranny sensor ran cleaner trough the gas. had the battery disconnected when replacing all sensors evrything i can think of!
Please help, I hope I'm not dealing with a PCM problem

I feel like if I can get rid of this I scored a pretty good deal

 

Have a look at this page. See if that doesn't help shed some light on the issue.

 

I am having the same issue with a 99 Ram 1500 5.9l, cant clear the p0505 check engine light code. Cleared code by disconnecting battery and with scanner. Code clears if I unplug IAC , goes back on when I plug it back in (plugged in new IAC without connecting it to Throttle body, code comes back). Wires and connectors look okay, iac replaced twice, replacement ecm. Runs fine at all speeds and at idle.

 

The majority of the time I encounter that code, it's the PCM at fault. Where did the PCM come from that you put in it? There is an 8 page test for that code, which I won't go into depth about, BUT the main things you need to look for are:



1 None of the IAC wires should have continuity with any of the other IAC wires.

2 None of the IAC wires should have more than 5 volts on them with the engine running and the IAC unplugged.

3 None of the IAC wires should have continuity to ground.



4 1 & 3 are done with the PCM and the IAC unplugged.

 

Thought IAC was 12 volts?

 

(Jiveo) Bought the ECU on ebay, rebuilt. Could be the culprit. I will check the continuity and see if I come up with anything. Thanks

 

Bought the ECU on ebay, rebuilt. Could be the culprit. I will check the continuity and see if I come up with anything. Thanks

 

1 and 3 check out ok, but i get voltage oscillating between zero and 13 volts on each of the contacts on IAC connector

 

I downloaded a 2001 ram manual and it shows 12v for each of the four wires to IAC not 5V. So if this is true it may not be the PCM at fault. So with all these tests showing everything is working, why cant I clear the code.

 

Reset the PCM. (disconnect battery, turn on headlights. turn off headlights, hook battery back up.)

Turn the key to "ON", but, don't start the truck yet. Count to ten. Start truck. DO NOT touch the gas. Let the truck idle for a few minutes. Should flare to around 1500 at startup, slow to 1000 when cold, and idle down to around 700 or so when fully warmed.