2000 Dodge Ram 1500 Van issues

Reply

  #1  
Old 07-15-08, 03:51 PM
Member
Thread Starter
Join Date: Jul 2008
Location: USA
Posts: 11
Question 2000 Dodge Ram 1500 Van issues

Hi,
The vehicle:
2000 Dodge Ram 1500 Van 5.2L 318cid V8

First Question:
Does anyone know how to tell if the PCM needs to be replaced besides by actually replacing it?
Is there a way to test the PCM? or does a person have to go get a remanufactured one to find out if the PCM is the cause of the problems?

The Problems:
First there was an intermittent problem.
Sometimes when the vehicle is started it dies immediately.
Start it again, giving a little bit of gas at the same time as turning the key, van starts but dies immediately when taking foot off of accelerator to put into gear. This problem can go on as long as the van feels like doing it.
It cranks over and starts just fine.

The next problem was the check engine light came on.

The most recent problem now is that it backfires, both when first accelerating and while driving.
The backfiring is also an intermittent problem.

Had a guy scan the van and the code was: P0505
Idle Air Control Motor Circuits
The description of the Diagnostic Trouble Code is:
A Shorted or Open Condition Detected in One or More of the Idle Air Control Motor Circuits.

I don't have a very good clue what that means.

So far this guy has gotten a little over $300.00, In return I have a new IAC that the guy didn't install because he says now that the PCM needs replaced and he didn't want to put the new IAC on until after the PCM was replaced just in case the IAC could become damaged if it was replaced before the PCM is replaced.
Oh, and also for the $300.00 the guy also used his scan tool on the van.
Somehow I feel a little taken advantage of and can't afford to be taken advantage of anymore by buying a PCM if one is not needed.
I mean the guy says oh you need a new IAC, I pay him for one along with labor fees to install the part, He buys the part, doesn't install it but tells me that I now need to replace the PCM.

Any and all info. and advice will be appreciated.

Thank You,
 
Sponsored Links
  #2  
Old 07-15-08, 04:39 PM
Unclediezel's Avatar
Member
Join Date: Dec 2006
Location: Northeastern PA.
Posts: 2,230
Find a new Mechanic......


Unless he is using a "Code reader" only.......Anything with Bi directional controls can actuate an IAC motor by command thru The PCM and the vehicles wiring harness.....

As far as damaging the part.......I doubt it...a BAD IAC can damage a PCM...But I have yet to see the opposite hold true.

I do agree with the Code matching the symptom.......Your IAC controls Idle speed, as opposed to the THrottle stop screw that we used years ago.....If your IAC locked up in a Closed position, you have NO Automatic Idle speed adjustment,and the engine just wont run fast enough to keep itself running....The opposite....Locked open....would cause the engine to scream away after starting.
 
  #3  
Old 07-15-08, 04:57 PM
billys68ss's Avatar
Member
Join Date: May 2003
Location: USA
Posts: 1,459
I really think you need to go to a different shop. The check engine light is an indicator that there is a problem. The first thing that he should have done was to go through the diagnostic procedure for the code. The IAC circuits can be tested without condemning any parts. And I certainly would not condemn a PCM without having exhausted the proper testing.
If you already paid this guy to do the repairs and he didnt even install the parts you paid him to install then cut your losses and move on to another shop.
Hope this helps ya,
Billy
 
  #4  
Old 07-17-08, 04:36 AM
Member
Thread Starter
Join Date: Jul 2008
Location: USA
Posts: 11
Originally Posted by billys68ss View Post
I really think you need to go to a different shop. The check engine light is an indicator that there is a problem. The first thing that he should have done was to go through the diagnostic procedure for the code. The IAC circuits can be tested without condemning any parts. And I certainly would not condemn a PCM without having exhausted the proper testing.
If you already paid this guy to do the repairs and he didnt even install the parts you paid him to install then cut your losses and move on to another shop.
Hope this helps ya,
Billy
I appreciate your info.
I have already done away with the mechanic.
Do you know where I could find info. on performing the correct diagnostic procedure for code P0505?
How is the IAC Motor circuit tested?
Is there a way to know if the PCM is bad? or a way to check the PCM?
Your info. is appreciated.
Thank You.
 
  #5  
Old 07-17-08, 06:25 AM
Member
Thread Starter
Join Date: Jul 2008
Location: USA
Posts: 11
I appreciate your info.
I have already done away with the mechanic.

I am a little confused with your reply so I'm gonna ask you a few more questions.
It's not that your reply was confusing, it's just that I want to be sure that I am understanding what you are saying.

This first question is probably gonna sound dumb....
So here it goes.....
When you said , "Unless he is using a "Code reader" only"
are you asking if all he did was the diagnostic scan that produced the "P0505" code?
If so, then I will tell you that he did the scan tool and he also said that he used his "meter?" to check the pins coming off of the PCM.
He said he tried it both ways and got zeros one way and I think fours and/or sixes the other way.
He also said that he looked for burned up wires but didn't find any.
With the IAC Motor that he was supposed to replace he said that he just cleaned up the old one and put it back on the van.

Now my next dumb question is about what you said next,.. "Anything with Bi directional controls can actuate an IAC motor by command thru The PCM and the vehicles wiring harness",
I'm sorry, but could you please dumb this one down for me?
Do you mean something like an ohm meter or multi-meter or something else?
If so, well, that is the only part of your statement that I understand. If you don't mind, please feel free to elaborate on this statement.

And, last question concerning your reply:
You stated, "As far as damaging the part.......I doubt it...a BAD IAC can damage a PCM...But I have yet to see the opposite hold true."
So then if my original IAC Motor is bad, and instead of being replaced (with the new one that is sitting its box on my kitchen table), the original is just cleaned up and then put back on the van, then the risk of damaging my PCM is being taken every time the vehicle is driven?
And rather than run that risk , Should I go ahead and install the new IAC Motor since I have it anyway?

Do you know where I could find info. on performing the correct diagnostic procedure for code P0505?

How is the IAC Motor circuit tested?

Is there a way to know if the PCM is bad? or a way to check the PCM?

Would the IAC Motor or the PCM cause the backfiring?
The backfiring is happening more and more often.

Your info. is appreciated.
Thank You.
 
  #6  
Old 07-17-08, 05:53 PM
Unclediezel's Avatar
Member
Join Date: Dec 2006
Location: Northeastern PA.
Posts: 2,230
There are several types of scan tools available. They vary in price, capability, accuracy and dependability....Most Major Car manufacturers have their own model for their specific products.......

I work for Chrysler, and currently ,our scan tool is wireless, PC based, with a built in flight recorder. It does everything from reading codes, to Component and system tests, to starting the vehicle from a computer terminal 75 feet away. The operators manual is well over 1000 pages, and the tool itself can be quite overwhelming. The 39.95 model that can be purchased at any auto parts store , can only read "EMission System" codes, and has no diagnostic capabilities.

By "Bi-Directional...I mean that the vehicle can talk to the scan tool , and the scan tool is capable of talking back. With this "Cross -Talk" , the technician is capable of "Actuating" or "Testing " various components and their ability to respond to commands within their own environment.

The draw back to installing the new IAC yourself, is ...In the event the PCM is damaged, it will not be capable of Commanding a response from the IAC. This may very well leave you with an uncontrollably fast Idle, making the vehicle inoperative.

As for Backfiring.....Not usually, but I suppose it is possible....

As a layman...picking out a Bad PCM is a Crapshoot....Its Better left to the pros, since a replacement PCM will require programming before it is functional.
B
 
  #7  
Old 07-17-08, 09:56 PM
Member
Thread Starter
Join Date: Jul 2008
Location: USA
Posts: 11
Thank You Very Much for your help so far.
So since the guy first said the IAC Motor is bad we should not put the new one in until after we replace the PCM which may or may not be bad?
Really Appreciate Any Info
 
  #8  
Old 07-17-08, 11:35 PM
Member
Thread Starter
Join Date: Jul 2008
Location: USA
Posts: 11
Oh, about the scan tool.
The one that gave the P0505 code is one of those handheld types.
So if the handheld ones are for reading Emission System codes then the P0505 code that points to the IAC circuit I would think is on the right track, based on the problems that the van is having.
And even though the guy originally said the IAC Motor needed replaced, and then later decided that the PCM should also be replaced, it would be best to go ahead and wait to install the new IAC Motor until after we are able to get a new PCM.
The guy determined the IAC from his scan tool code and he determined the PCM from the zero's on one way and 4/6's the other way results that he got with his ohm meter.
What I understand about this guys ohm results is that he put the probes on each pin on the PCM that go to the IAC. First he did one probe (red+) on PCM pin and the other probe (black-) on wire harness that goes to IAC Motor, then he reversed the probes (black- on PCM, red+ on Wire Harness).
That is why he had readings of fours and/or sixes and also readings of zeros. And that is why he determined that the PCM needs replaced.
So are the tests that this guy said he did enough to go on as far as condemning the PCM and IAC Motor?
And if not, what more should be done?
Also, if the PCM really isn't bad, will it become bad by keep running the vehicle with a bad ICM Motor?

Remember, the start of the problems was intermittent, vehicle starts fine just occasionally it dies immediately when accelerator is let up on, such as at a stop.
The check engine light came on later, and the backfiring is something fairly new but very often.
We just want to try to be fairly sure that we aren't buying parts that aren't going to fix the problem. After all we just spent $300.00 and bought a new IAC Motor and so far the only thing that is different is that the guy still wants $40.00 more and now the van sounds like it has a vacuum leak at the Throttle Body Gasket. Oh, and we know that the PCM may or may not be bad.
Would the ohm meter results be good to go on?
Again, Any info. helps and is Appreciated,
Thank You
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes