2001 Dodge Intrepid Almost stalls then Revs? Code P0601

Tiny
SDINEEN
  • MEMBER
  • 2001 DODGE INTREPID
  • 6 CYL
  • FWD
  • AUTOMATIC
  • 175,080 MILES
1. Very close to every 10 seconds while idling in park engine drops down to 200 RPM, s for a second, and bangs back up to 1,500
2. If you are driving and on the accelerator, this behavior is displayed through a quick lurch. It feels like you are hitting a pothole. (Doesn't display issue while coasting)
3. At lights, etc, car does sometimes stalls completely
4. Happens regardless of AC being on/off
5. Engine light on and code P0601, problem with "Int control module mem check sum error"
6. Car recently did get Hot due to leaking water outlet (resolved thanks to this forum). Wondering if relay or ECM got toasted a bit (did save from excessive heat by firing up the Heat full blast).
7. Probably just ironic but started almost exactly after hitting 175,000 miles?
8. Car has been flawless in last 4 years before this.

Any ideas besides take it to a dealer. I have no idea who the dealer is (3rd owner) and I'm really worried about what else they'll whip up $$ wise. See Ebay has a bunch of new ECM's that can be programmed for you, but not sure this is false positive code, and would prefer not to start there unless smartest option.
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Wednesday, July 7th, 2010 AT 10:37 PM

17 Replies

Tiny
OBXAUTOMEDIC
  • EXPERT
Hello,

Ok, well lets not be to concerned with the PCM right now. Just because the engine overheated doesn't mean the PCM was affected or any Relays.

The most likely and common cause is the IAC (Idle Air Control) Valve or some call it the Idle Speed Control Valve.

The problem may be a buildup of carbon or fuel varnish deposits.

It can be removed and cleaned first before replacing.
The cost of replacement will be between $73 and $130.

To clean just use some Carb Cleaner and spray into the opening, and clean the Plunger on the Valve itself. Let soak for 5 minutes or so then spray it again. Reinstall and start vehicle rev engine to 1500 for about 2 minutes or if there is any white smoke till white smoke clears.

Below is a pic of Valve.
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Sunday, July 11th, 2010 AT 8:20 AM
Tiny
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Thanks, I'll try that. Would the "seafoam" treatment be the best technique, or carb cleaner? I just performed that routine on my 1995 Astro and helped a lot. Sorry, didn't even think of trying here if that's a good idea.
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Sunday, July 11th, 2010 AT 11:36 AM
Tiny
OBXAUTOMEDIC
  • EXPERT
You can try the Sea Foam. Sometimes with the newer vehicles a large vacuum leak will cause stalling. So, I will usually just remove the valve and clean it. It's a little more work but I think it work a little better cause if there are some pretty good sized carbon depisits you can use a small flat screw driver to scrape it off, were as the sea foam may not get it off, at least not with one treatment. Also there are times when depending on were the Valve is located that would be easier the clean it remove the Throttle Body and you would need a new gasket if you do.

.
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Wednesday, July 14th, 2010 AT 8:49 AM
Tiny
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Does that help at all in troubleshooting? I soaked it in seafoam, plus hit the housing with carb cleaner (since it was spray, I was hoping a seafoam soak, as it was a pour, was the way to go). Put back together and it was fine for 60 seconds. Would clearing the code help (I'd have to head back to autozone for their Scanner).

Also, the piece was exactly like yours EXCEPT it had a plastic tube, like a straw, covering everything "spring" in your picture. I assume leave that alone. I scrubbed the rest of the thing the best as possible. Any other suggestions super appreciated! Oh. And a lot of what came out the pipe, besides white smoke, was water?
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Saturday, July 17th, 2010 AT 3:58 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Ok, misunderstanding with the seafoam thing.

The way I do the seafoam is by removing a vacuum line from the intake or the Plenum and replace with one long enough to read from the vacuum nipple to the can of seafoam then start the vehicle and let the vacuum inhale the seafoam to clean intake or plenum along with valves.

Ok, back to the IAC. Did you try pushing the plunger in to make sure it was moving and not froze up?
Here is a simple test.

To check the IAC motor remove the unit. With the wires connected turn the key to the "on" position without starting the engine. The IAC should move in or out. If the IAC motor does nothing it has probably failed. Replace it with a new unit.

Clearing the codes shouldn't make a difference. Usually once the problem is fixed the vehicle will run normally and the code will clear out after either 500 - 1000 miles or 50 - 75 key starts. But I usually suggest having codes cleared at your local parts store once repair is completed.

.
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Saturday, July 17th, 2010 AT 8:22 PM
Tiny
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Soaked the IAC in it (just the bottom spring portion) and did the treatment as you described in the vacuum hose.

Without it connected, I did press the IAC spring, and it went in, but did not return back out. Does that give any info?

I'll do the test exactly as you described later tonight. Thank you!
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Sunday, July 18th, 2010 AT 8:17 AM
Tiny
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Ok, I believe it should have come back out, but not sure.

The other test will tell for sure though.

.
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Sunday, July 18th, 2010 AT 1:34 PM
Tiny
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Well, it did not move at Key on, ignition off. I pushed the sucker all the way in and tried again, still nothing. After reconnecting, and formally firing back up, I had to let the car sit and idle a good 5 minutes before it got itself back into the normal idle range. Down from 3.5k rpm, so assume that's from me compacting it like I did. I guess I need to pickup a new one tomorrow! I'll report back.
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Sunday, July 18th, 2010 AT 8:01 PM
Tiny
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New one does nothing to help the situation. Same stalling, speed up cycle every 10 seconds. Assume I need a new PCM? Additional info.

1. Every time the cycle repeats the ac compressor goes off. It eventually picks back up again, but I get about 4 seconds off it running during the cycle meaning my cooling is 40% tops.

Any help would be super appreciated.

Thanks!
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Monday, July 26th, 2010 AT 10:01 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Ok, Let me put your mind at ease about the P0601 code.

P0601 OBD-II Trouble Code
Technical DescriptionInternal Control Module Memory Check Sum Error

What does that mean?

Basically that means that there is an interal fault in the Powertrain Control Module (PCM). There have been many reported PCM failures on Chrysler/Dodge products although it is possible for this to happen on any vehicle. In Dodge/Chrysler products, a P0601 trouble code means that a serial communication failed inside the computer at least 6 times.

Symptoms

Likely, no symptoms will be discernible to the driver, other than the illuminated Check Engine Light. Typically the engine runs fine, gauges work, etc.

Causes

A code P0601 in most cases means the PCM has gone bad. This is possibly due to a short-circuit inside the PCM. Or, if you disconnect the wires/connector from the PCM while the battery is still connected, that may also cause this code.

Possible Solutions

With a P0601 OBD-II trouble code, the most common fix is to replace and reprogram the PCM. In a few cases the dealer may be able to reflash the PCM and get it working. But more than likely the PCM will need to be replaced and reprogrammed (we recommend you take it to a dealership for this). The good news is it *may* be covered under your emmissions warranty. So even if you're out of bumper-to-bumper warranty or powertrain warranty, check your warranty guide or dealer to see if this is covered.

Other people have reported that they cleared the code only for it to return again and again. Keep in mind that most shops can replace the PCM but not all can program it.

.
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Wednesday, July 28th, 2010 AT 7:40 PM
Tiny
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Thanks for trying. I'll get a Programmed PCM from ebay and let you know how it goes. I just wanted to CONFIRM it was a PCM, and not false positive. I unfortunately have major symptoms, and not just an engine light on. Wish I was that lucky.
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Wednesday, July 28th, 2010 AT 7:47 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Ok, Now let try a few thing....

First - When was last time Fuel Filter was changed. If been a while may be good idea to change it. A partially clogged fuel filter can cause engine surge.

Next - will need to check Fuel Pressure - Check link below for Video on how to test....

http://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm

The next possiblity is the Catylitic Converter - To check you can remove the O2 Sensors in the Exhaust Manifolds and run car if Surge is gone then replace Cat.

Also Recheck for Vacuum Leaks

.
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Wednesday, July 28th, 2010 AT 7:49 PM
Tiny
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Thanks! I will look into the 02 Sensor because I can understand how this may have something to do with it. Honestly I can't believe how the fuel pressure and filter may be a problem. I'll tell you why. The problem (stall/rev cycle) on first start ONLY varies. It can be 15 seconds, or 25, but is always a longer period than after it happens once. After it happens once, it happens every 10 seconds PERIOD while running. I litterally count while I drive now to avoid the lurch/jerk while accelerating, backing off the pedal the moment its gonna hit. I can't believe this is a clog, it has to be electronic, or sensor. On the fuel pressure/pump? What do you think? Really a possible culprit based on that info? Sorry for not being clearer on the symptom.
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Thursday, July 29th, 2010 AT 9:30 AM
Tiny
OBXAUTOMEDIC
  • EXPERT
Ok, so since you say that it happens on first start only, then if you turn it off and restart it the problem is gone?

Ok, now with a partially clogged filter the pressure going through the filter can fluctuate causing engine surge.

Now, a weak fuel pump can do the same thing.

Also I was referring to the Cat being partially clogged and if you remove the 2 O2 sensors in the Exhaust Manifold and start the vehicle if the surge is gone then you have a failing Catylitic Converter and you will need to replace it.

The PCM being bad, I don't believe has anything to do with the engine surge.

.
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Thursday, July 29th, 2010 AT 8:01 PM
Tiny
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No. The symptom is constant. It is only different on first start. Different in that it takes longer to begin, from 15-25 seconds. Then "it" happens every 10 seconds. If you turn it off and restart it, you will wait 15-25 seconds again. Then you will wait 10 seconds forever after while running.

The stall and surge (aka "it") are immediately after each other. As a P0601 no means = change PCM, absolutely, and without a doubt, I will do that first. If the problem continues I will definitely hit the filter and pump. Again, I don't see how it happens like an atomic clock at 10 seconds, but what else have I got. Thanks again!
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Thursday, July 29th, 2010 AT 8:22 PM
Tiny
SDINEEN
  • MEMBER
Used the PCM refurbers on ebay (I chose Solo) and I'm all hooked up. Definitely the PCM. Apparently the troubleshooting flow chart from Dodge which someone was kind enough to forward me from another forum had a one step flow chart. First step = replace PCM. No other options. Live and learn I guess. Wonder why it decided to bite it? Thanks for all your input!
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Sunday, August 8th, 2010 AT 9:41 PM
Tiny
OBXAUTOMEDIC
  • EXPERT
Glad you are all fixed. Just not sure why the PCM would cause the surge. A bad PCM will go into a default mode and there is usually no drivability issues.

Congrats on the fix.

.
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Monday, August 9th, 2010 AT 4:38 PM

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