What are my options for replacing the PCM?

Tiny
ENE4589
  • MEMBER
  • 1995 DODGE STRATUS
  • 190,000 MILES
My PCM in my 95 Dodge Stratus (2.4 engine) has gone out.

I just needed to know what are my options:

Can my current PCM be repaired?

Are there any other vehicles that would have campatible PCM's that I could use?

Or could I get one out of the same exact vehicle and it would work?

I am being told different things by different people, so I am just trying to get as much info as possible.

Any help would be greatly appreciated!

Thank you!

Monday, November 14th, 2011 AT 7:04 PM

12 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,749 POSTS
What are the symptoms? Chrysler had extremely little Engine Computer trouble in the late '80s to mid '90s. Any '95 Stratus, Cirrus, or Breeze computer from the same engine size will work. It will not have to be programmed to make it work, (that was B.S. GM started years later), although there may be software updates that are available. They call that "flashing" the computer.
Was this
answer
helpful?
Yes
No
Monday, November 14th, 2011 AT 7:32 PM
Tiny
ENE4589
  • MEMBER
  • 6 POSTS
Thank you so much for your response.

I was taking my daughter to school one morning. The car died at a stoplight but started right back up. We got to the school.I took her in and when I came back out to the car it would not start. It makes the "rrr rrr rrr" sound but will not start. My dad is who is working on the car. He came and thought the fuel pump had gone out because it was not kicking on. We towed it home and he checked all the fuses. All good. He dropped the tank and took the fuel pump out. He hooked a new fuel pump up and still nothing. He had the new fuel pump checked (on a jumper) and it kicked on AND so did the old one. So it was not that. But checked the plug in where the fuel pump connects and there was no power from the connector. He was told to check the fuel relay switch/fuse and the ASD switch/fuse and both of those checked out ok. Then he was told to check the crankshaft sensor and (forgive me I forgot the name of the other one) the camshaft sensor? And both of those were ok too. He hooked up the thing for codes but it kept saying that no codes were found. He finally towed it to a mechanic and the mechanic told him that it was the Powertrain Control Module. He has been told that it is very rare but he doesn't know what else to try. And since his mechanic said that is what it is? The mechanic did say the same thing you did. That he could get one from the same engine and it would work without being "flashed" so that is a plus.

Any input would be greatly appreciated. Thank you so much!
Was this
answer
helpful?
Yes
No
Monday, November 14th, 2011 AT 11:37 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,254 POSTS
PCM's are generally non repairable. As far as a replacement, you can get one from the same type of vehicle but it must have the exact same part number, no varaiations?
Was this
answer
helpful?
Yes
No
Monday, November 14th, 2011 AT 11:50 PM
Tiny
ENE4589
  • MEMBER
  • 6 POSTS
Oh and forgot to say that the car has no spark either.
Was this
answer
helpful?
Yes
No
Monday, November 14th, 2011 AT 11:51 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,254 POSTS
That could be coming from the PCM, a bad crank sensor.
Was this
answer
helpful?
Yes
No
Tuesday, November 15th, 2011 AT 12:03 AM
Tiny
CARADIODOC
  • MECHANIC
  • 33,749 POSTS
Okay, first of all you should understand that it is normal to have no voltage to the fuel pump. Voltage will appear there for just one second after turning on the ignition switch. You should hear the hum of the pump for that one second. The voltage must return during engine rotation, (cranking or running).

You must also check for spark when you have a no start condition. Too many people find just the fuel pump dead or just missing spark and get hung up on that one system. An easier place to look is the feed wire to the ignition coil, any injector, or either small wire on the back of the alternator. It should be dark green with an orange stripe. A digital voltmeter might not respond fast enough so if you have a test light, that might be more accurate. It should light up for one second when you turn on the ignition switch, then go off. If it does, that proves the automatic shutdown (ASD) relay and wiring are okay and the Engine Computer has control over it.

What is important is that voltage must come back during cranking. If it does, then you must continue diagnosing just the fuel pump or spark circuits, but it's much more common to find the voltage does not come back during cranking. When the computer turns the ASD relay on for the first second, it is usually okay. THEN, when it doesn't turn on the relay during cranking, suspect the crankshaft position sensor or the camshaft position sensor. It's the signals from those two sensors when the engine is rotating that tells the computer to turn the ASD relay on.

If the Check Engine light turned on, there will be at least one stored diagnostic fault code in the computer. That will lead to the circuit that needs further diagnosis, but usually it will just be caused by a defective sensor. If there is no code in memory, a scanner that can display live sensor data is needed. It will display both sensors and "no" or "present" for those two signals. If the Engine Computer is recognizing both signals as present, but not turning on the ASD relay, the computer itself could be defective, but that isn't common.
Was this
answer
helpful?
Yes
No
Tuesday, November 15th, 2011 AT 12:13 AM
Tiny
ENE4589
  • MEMBER
  • 6 POSTS
Thank you for so much information. It is greaty appreciated.

I did have one comment. The fuel pump does not even hum for that one second you were talking about. It makes no noise at all at any time. Not even for that one second. Neither does the voltage for the one second.
Was this
answer
helpful?
Yes
No
Tuesday, November 15th, 2011 AT 4:02 PM
Tiny
JACOBANDNICKOLAS
  • MECHANIC
  • 108,254 POSTS
Check to see if there is power to the fuel pump relay.
Was this
answer
helpful?
Yes
No
Tuesday, November 15th, 2011 AT 5:57 PM
Tiny
ENE4589
  • MEMBER
  • 6 POSTS
There is no power the fuel pump relay. However, if he puts a jumper wire on the 30 and the 87 terminals in the fuse relay box, then he gets voltage to the fuelpump connector under the back seat AND the fuel pump kicks on and runs. ONLY with the jumper wire on 30 and 87. And this is with the key off. And when I test the ASD relay with the voltage tester. Terminal 30 lights up with the key off like it's supposed to. However terminal 86 lights up with the key off also BUT is only supposed to light up when the key is on is what he is told.
Was this
answer
helpful?
Yes
No
Tuesday, November 15th, 2011 AT 8:33 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,749 POSTS
We know your very first sentence is wrong because there has to be voltage if the pump runs when 30 and 87 are connected. That proves the entire switched part of the circuit is working and the fuse for that circuit is okay.

Terminal 86 should have voltage all the time. The Engine Computer grounds terminal 85 to turn the relay on. If you can poke a small piece of wire into terminal 85, AND plug the relay in, you'll find 12 volts on that terminal too with a digital voltmeter. It's feeding through the relay's coil from terminal 86. If you test it with a test light, they are so low in resistance that it may conduct enough current to turn the relay on. Either way, that does indeed lead to the computer as the primary suspect if it's not turning the relay on for even that first one second. Rats; I was hoping for a simpler, less expensive solution.
Was this
answer
helpful?
Yes
No
Wednesday, November 16th, 2011 AT 12:46 AM
Tiny
ENE4589
  • MEMBER
  • 6 POSTS
I apologize for the mistake in my first sentence :-) I am getting all the info from my dad (and I am female) so I sometimes get things confused as he's telling me since he repeats things over and over and over again, mostly skipping around all over the place. Lol.

But I thank you so much for all of your information. And for confirming that it does indeed lead to the computer being bad. You have been more helpful than most people we have talked to and you stuck out the question til the end! I will be sure and post what happens after we replace the computer. Once again, thank you so much. It was greatly appreciated! :-)
Was this
answer
helpful?
Yes
No
Wednesday, November 16th, 2011 AT 1:32 PM
Tiny
CARADIODOC
  • MECHANIC
  • 33,749 POSTS
Didn't mean to imply YOU were wrong. I meant the information was wrong. That happens all the time when taking readings in tvs and car radios. Those wrong measurements send us down the wrong path so we often take two or three readings at different points in the same circuit to double-check ourselves. The problems are multiplied when two people become involved and things get mixed up.

Will wait to hear the car is fixed.
Was this
answer
helpful?
Yes
No
Wednesday, November 16th, 2011 AT 9:30 PM

Please login or register to post a reply.

Sponsored links