Hello everybody.
2000
RAM 1500
V8 5.9
Today I installed an scan tool and got "idle malfunction" P0505. Replaced IAC. Still the same code. The IAC removed didn't looks good but I didn't notice any difference when the new part was installed.The scanner is showing problems on both O2 sensors. You guys think the next step should be O2 sensors replacement?
Thank's in advance.

 

I'd replace the upstream (pre-cat) o2 sensor first, it seems to be the one that goes bad.

 

hold on. what codes do you have ? you have to list the actual codes if you want us to help. you also have to describe any problems that you are experiencing.


regarding P0505.
did you clean the IAC well in the TB?
and did you reset the PCM by disconnecting negative battery cable and turning on headlights for 30 seconds. if not, do that.

https://dodgeforum.com/forum/dodge-r...505-still.html

on the IAC, don't push, pull, twist, or turn the pintle. it will break it.
also check the electrical connector and wiring. make sure of no damage such as rats or squirrels chewing on the wiring.

post back your results.

 

considering the data they provide is being ignored at idle, i'd say that's likely not the problem. make sure the iac is clean, the pigtail in in good condition, and there is power at the pigtail at idle.

 

I replaced the IAC for a new part. There is voltage on A and B terminals (12V). There's no another error code, only P0505. When I use the "Read monitors" on the scan, it showed "inc" for both O2 sensors, but not others codes. I remember when I bought this truck 4 years ago, always the O2 sensors were in problem (as per scan tool). I didn't notice any RPM variation when I remove the conector from the IAC. Is it necessary to clean the TB body where the head ofthe IAC is located? Maybe is very dirty as the IAC was.

 

No, I did not disconect the battery wire, I will do right now and will installed back when comeback from work. I will let you know later today

 

The O2 sensors will mess with your motor. Replace them, they don't last the lifetime of the truck.

 

Ok, here we go:
-8 new spark plugs Champion Double platinum
-New IAC
-New air filter
-Removed and cleaned TB
-New thermostat ( Old one was opened all time)
-New both O2 sensors
-Checked wiring for O2 and looks clean and intact

My truck is worst and worst. Now is showing the same code "Idle malfunction" and when I'm driving and then stop, RPM didn't decrease, they remains at 1000 RPM ....

 

Yesterday I was checking some vacum hoses and tighting the junctions with tie wraps. I tested again today and noticed some change in its behavior:
-After reach 195 degrees, loose the idle, remains at 1000 RPM or 1500 RPM.
-Heater inside cabinet start to work. Never worked since I bought the truck. Is there any relation between the heater and the vacum?
- I hear a whistle when I'm driving and decrease the aceleration.
-Checked the fuel economy: 10 MPG combine city and highway with A/C working

What's the next step to recover the idle spped? What I did wrong?

 

any help??