I got a 2001 Sport 3.3 GAS(not FLEX) with P0601. I've been digging around the net and in the van. In my case it looks like it was caused by a bad-leaky battery the last owner ran in it a while, but this is unconfirmed till I go get a flash and, if the local Dodge/Chrysler/Jeep dealer does it, diagnoses of the actual cause of the P0601. The last owner had a lot of PCM work done from what I see on paperwork, though, all by a dealership.

A few bullet points from massive amounts of reading(since it'd take forever and cost a lot to actually learn how the PCM is designed and works(reverse engineering)):

• Like with tranny work you can easily spent 2x KBB value of the vehicle paying even dealership mechanics to brute force a working fix.. They charge at least $750.00 for a replacement which is basically what most of them will first push on you for the sake of their convenience..
• P0601 is caused by x amount of start-ups where the stored integers in the PCM firmware don't equal equated ones from the values returned by all the sensors and circuit resistance checks
• Fried injector harnesses tend to cause it in '01+ caravans but bad performance and copper showing on the injector harness make this obvious
• Circuits behind other controllers and off of DLC can't cause it and are always handled by other OBDII codes
• Cases where everything is still functioning tend to be from batteries causing altenator spikes and intermitted wiring shorts caused by heat and vibration.
• Grounds don't cause it but standard ground checks can sometimes lead you to discover major component failures on the DLC that may be causing it
• Short probes like wireless ones(ex PowerProbe ECT2000) which typically make finding even shorts deep in the main wiring harness easy are worthless for finding PCB based faults and DLC shorts because it's digitical signal wire that communicates in packets over module interfaces. Multi-meter cont. tests per-pin only work.
• For $1,300 to $2,000 you can flash a TCM, PCM, ECM from your home computer using manufacturer databases over the internet and without any special business license or certification. Most small shops don't do it because it doesn't see enough service for the investment
• No code scanner on the planet can clear it. It supposedly goes away after x start-ups with accurate data matches, but this doesn't seem accurate. It takes a new flash or replacement
• Autozone is the best non-dealership source for PCMs. They come with 1 year warranties and you just supply mileage and VIN for non-transponder-key vehicles. Maybe a serial number off your PCM too. You get $70 off the $250.00 price when you do the core charge rebate. RockAuto and AutoComputerExchange are sometimes reliable too, but stay away from FL based All Computer Exchange(A.C.E. is also FL based which is suspicious and both are Ebay)

 

Thanks for posting your findings. Good info there. Your question is and has been up for debate for years. Some techs say replace the PCM as a sure fire fix. Others say look elsewhere first. I would say as long as there's a chance it's not a PCM causing it take the time to do some troubleshooting. It may be well worth the time and effort as it's a pricey little box and can be a hassle at times. Over many years of cruising forums I've read of one or two instances of external faults flagging a P0601. Round and round we go.

Some report they've driven with a P0601 for years without any adverse symptoms. Others aren't so lucky.

Autozone 1 year warranty. Others have a lifetime warranty.

 

What's interesting is the PCM is a single board computer and if there was an actual hardware glitch even on the interface pins or traces it doesn't even have fault design for anything inside of itself and would simply overload the first under-rated analog component on the faulty trace on it's PCB and be a paperweight.. This means it's logically impossible for it to be an internal issue.

I've also read about it going away immediately after changing an ignition switch(which I think is only on the DLC harness on chip-key vehicles) and after fixing an unspecified short buried deep in some insulation(I can't think of anything on DLC harness in insulation(wiper tray and inside firewall has it), so probably one of the under-dash controller regulators or something.

**The one edge everyone has when tackling this is it's a fact anything behind other controllers and off DLC can't cause it, neither can the PCM itself, and battery only causes it through a not so well know feature that spikes alternator output when the battery DLC reports low; if this happens x time P0601 is set and can't be cleared without a flash unless there really is a x number of times with matching checksums that clears it; if x valid checksums does clear it, it's likely in the tens which is why there are barely any reports of it working out of staggering amounts of online reported experiences.


Regarding AutoZone PCM: Yeah but Autozone doesn't have tens of thousands of horror stories around theirs.. RockAuto and All-Computer are the most prominent based purely on reviews outsize autozone and shop or dealer flashes and replacements. I was actually personally referred to RockAuto by a veteran certified mechanic and long-time business owner with a flawless reputation in the area he serves; RockAuto does good enough to buy airtime for networked TV commercials too.

 

You can drive your car around with a P0601 as long as you want....IF that's all it is.


The problem you may encounter with the P0601 condition, or just about any P0600 series DTC, is that the condition can/may mask other DTCs from being generated. Therefore, you risk not knowing what other issues are about to surface or are already brewing. I have run into this many, many times. The PCM is replaced for the P0601, then other VALID and active DTCs join the party afterwards. The underlying/hidden DTCs can also be the culprit that caused the P0601 or P060..whatever in the first place.


The problem with reman PCMs is that if a PCM that had the P0601 lays dormant for a long period of time or goes through a reset procedure, it may not show up when the functionality test is done at the facility. It actually won't pop up until you install it on the car and run it for a few minutes.


I have had to replace remans several times, sometimes numerous times before I got a good one for just this reason (P0601 recurring). This MAY lead people to believe that their P0601 is caused by something else, which is not the case.....in this case. These issues come in batches. It doesn't necessarily matter what car line it is, just a specific PCM core.


I think the mistake people make in their logic, is using too much logic...lol. The reman pipelines play a big part. More of a part than the original engineering behind it.

 

That's true WHEN you order one outside of a dealer. All my points still stand, there is no such thing as a PCM that reports internal hardware faults, this DTC is based purely on x cycles where variables didn't match EEPROM stored table values inside the PCM. It's actually not expensive to have your factory PCM flashed at a dealership and even have a diagnostics done to find why it was logged($150-$300 for flash usually $100 for diagnostic I'm told)... IF you can get the tech to do it; some will simply refuse to serve you unless you just replace the entire unit and laugh at the request for diagnostic or basically go smoke a cigarette then come back and tell you to replace the whole unit still..

 

Well, I wish I had read this sooner.

We've had the P0301 on our '01 Dodge Stratus for a year now and I just got around to ordering a PCM from one of the vendors on ebay. :{

Local dealer wanted $1000 to replace the PCM that is in there...I assume that was a refurb PCM and the flash charge.

 

Have you had the vehicle tested for the P0301 misfire number 1 code? and the dealer will only sell a reman controller.

 

The big problem with these permanently written codes are they are never caused by stored codes(DTCs). They are caused by shorts and surges in front of other computers. Even if you get your plug and play PCM and hook it up you're not going to get any codes to help you see what caused the code. There may be codes there till the PCM sets the fault again but they aren't the cause.

These are basically uncaught faults in the PCM design. If you can still use your car it's not a blown driver either. Blown PCM drivers out-right kill, or take out, the entire PCB of the PCM. You're getting value mismatches in non-critical circuitry or even a bug or version difference in another computer.

Dealership techs are extremely lazy. If you rely on them to do their "analysis" and solve the problem you'll be having the problem again in months.

 

No I don't recall a test like that. Is it something only the dealer can do?

 

Well we have been driving the car for 18 months at least with the check engine light on without a problem.

When I have taken it for service they tell me the P0601 code is on "the computer is bad, but you can still drive it ok", so that's what we've been doing.
Just recently I had some AC work done, that guy scanned it and said it had an O2 sensor code pending. That was a new one to me, but I confirmed with an OBD scanner I bought at a tool store. It also confirmed the P0601 code.