2005 pt, starts but will not stay runing

[Bob0]

Starts, for bout 3seconds then shuts off, if you hold gas pedal so rpms around 1500, you can keep it running, we've changed all censers, and secruty system seems to be working fine! Also this is non turbo, thinking at this time problem maybe the CPM! Oh, the only code showing is idle air. Anybody with any ideas ?

Almost forgot, if you unhook battery for 2/3 days, it will start and run fine for about 20 minutes, then this ploblem starts again!

[LionPT]

Originally Posted by Bob0

Starts, for bout 3seconds then shuts off, if you hold gas pedal so rpms around 1500, you can keep it running, we've changed all censers, and secruty system seems to be working fine! Also this is non turbo, thinking at this time problem maybe the CPM! Oh, the only code showing is idle air. Anybody with any ideas ?

Almost forgot, if you unhook battery for 2/3 days, it will start and run fine for about 20 minutes, then this ploblem starts again!

What is the actual code..??

[Busted_PT]

it sounds to me that you need to clean or replace idle air control valve.

[Bob0]

I tried something yesterday that I read,,,, I read somewhere that the security and ecm computers need to sync together, and to do this you leave the key turned on for 3 to 4 hrs! well, I tried this and would you believe the pt runs great now,, !!!!

SO hopefully this takes care of the problem, now only time will tell!

So a big "thank you" to every one on here, I will keep you posted if this is a good fix!

[ptcruisersteve]

Originally Posted by Bob0

I tried something yesterday that I read,,,, I read somewhere that the security and ecm computers need to sync together, and to do this you leave the key turned on for 3 to 4 hrs! well, I tried this and would you believe the pt runs great now,, !!!!

SO hopefully this takes care of the problem, now only time will tell!

So a big "thank you" to every one on here, I will keep you posted if this is a good fix!

IF it happens again check to see if the red security light comes on on the dash. I always suggest the "leave the key turned on for 3 or 4 hours" if the little red security light is on due to the security immobilizer locking up. If the security light is not coming on I would recommend you have a battery load test done. The computers in the PT Cruisers are sensitive to voltage drops.

[Bob0]

Well
That didn't last long,,, this morning it started up and run good, went down the road bout a mile and shut it off, and came back out and went to restart it, and now we are back to same problem! "will not idle" , only code that shows up on my code reader is P0508, and has all along, we've even changed the idle air unit but no help, And the battery is in good shape and voltage is good!

I'm guessing now, but looks like I may have to change the ECM!

thanks again to all that has tried to help!

[ptcruisersteve]

P0508 - Idle Air Control Motor Sense Circuit Low Input Conditions:

Possible Causes:

1. IAC motor driver circuit is open or shorted to ground
2. IAC motor sense circuit is open or shorted to ground I
3. AC motor is damaged or it has failed
4. PCM has failed

A shorted IAC can damage the drivers in the PCM and that can also set a P0508 IAC valve sense circuit low trouble code. I would recommend checking the wires going to the IAC motor and if the wires are okay consider replacing the IAC motor before replacing the PCM.

[Bob0]

Originally Posted by ptcruisersteve

P0508 - Idle Air Control Motor Sense Circuit Low Input Conditions:

Possible Causes:

1. IAC motor driver circuit is open or shorted to ground
2. IAC motor sense circuit is open or shorted to ground I
3. AC motor is damaged or it has failed
4. PCM has failed

A shorted IAC can damage the drivers in the PCM and that can also set a P0508 IAC valve sense circuit low trouble code. I would recommend checking the wires going to the IAC motor and if the wires are okay consider replacing the IAC motor before replacing the PCM.

Let it set for a couple days and tried it, started up run fine, for bout 10 minutes, then back to same problem, time to save up some $$$ and a new ecm, thanks for ideas folks !

[Fk5]

Just in general, I am assuming that the security light is not/has never been on?

In that case, I would start by looking at the wiring near where you have been working. Something you did probably caused it to run better for a time. It is very rare that it is dumb luck, and it does not seem likely that the key on trick was the fix. Usually we moved something that caused the change.

[Bob0]

security light is not and has never been on!
also to let ya know some background, we were having same problem before we changed the motor, but this was changed because of very low compression in #2 cylinder, (50lbs!), also we've changed all censers after changing the motor! idle air unit has been changed also.