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Are Rebuilt ECM / PCM / ECU Any Good?

J

JeepDawg

NAXJA Forum User
Location
New Jersey
How long has yours lasted, and where did you buy it? There are a lot of horror stories of exchanging these things every month with some of the companies out there.
 
don't waste your money on a rebuilt one. Go to the junkyard and find one or try to buy a used one from someone on NAXJA. You'll save a loooot of money. And if you do buy a used one, it does not need to be reprogrammed as dealers tell you they do. Just plug it in and go.

I fried my pcm after it filled up with water! Got a used one on here for $40, works great. Rebuilt ones were $200-300.
 
Really? How long ago was this? And it's still working great? Unfortunately, I need it to pass inspection.....so I might have to have it reflashed.....I think.
 
I don't think there is actually anything inside that can be or need to be rebuilt (replaced, adjusted, anything).
Guess they just clean it up on the outside, check if it works, stick price tag on it and call it rebuilt.
 
JeepDawg said:
Really? How long ago was this? And it's still working great? Unfortunately, I need it to pass inspection.....so I might have to have it reflashed.....I think.
Click to expand...

It's been about 6 months since I put in the used one. No issues.

hmm, there are no vehicle inspections in FL, so I'm not sure if you might need to get it reflashed for the VIN to match. If you do, it costs about $100 at the dealer to do that. Still cheaper than buying a rebuilt one.
 
I wish it was that cheap up here... ECM's run about $100 at the junk yards near me....and the dealer would charge another $150-$200. I just don't want something that will leave me stranded on the side of the road....with my 2 year old in the back seat....ya' know!?!?!
 
Got my rebuilt computer at napa it was not reflashed with no problems
 
mr_W said:
I don't think there is actually anything inside that can be or need to be rebuilt (replaced, adjusted, anything).
Guess they just clean it up on the outside, check if it works, stick price tag on it and call it rebuilt.
Click to expand...

I think that's the case for most of the rebuilt units. The less reputable outfits don't even bother testing - they let the customers do that and just accept that they'll have a certain percentage of returns or exchanges. I'm willing to be that most of the "bad" units they take in trade work just fine.

Often the failure can be isolated to a specific chip or transistor, like maybe the FET transistors that drive the fuel injectors. The labor involved with digging out the potting material to replace the part can eat up a lot of profit though. Occasionally you might fix a unit by reprogramming, but that's pretty rare.
 
jeepster_259 said:
And if you do buy a used one, it does not need to be reprogrammed as dealers tell you they do.
Click to expand...

Is that true for the 200+ models with the electronic dash and odo? I thought the mileage was stored in the ECM. Do the abbreviated ODBII vehicle emissions inspections check the VIN stored in the computer?
 
lawsoncl said:
Is that true for the 200+ models with the electronic dash and odo? I thought the mileage was stored in the ECM. Do the abbreviated ODBII vehicle emissions inspections check the VIN stored in the computer?
Click to expand...

As far as I know, the mileage, etc. is stored in the gauge cluster. My 98 has the electronic gauges and everything was the same when I swapped computers.

I do believe the VIN is stored in the computer, so if you do have a vehicle inspection that checks this, you will need to have it re-flashed.

In regards to the original post, though, how do you know your ECM is bad? They rarely go bad and need to be replaced. Mine only went bad because the jeep sat in 4.5' deep water for 15 minutes waiting to get pulled out and the ECM filled up with water and shorted out. I finally diagnosed it as the ECM somewhat by process of elimination. What led me to the ECM was that the truck would shut off after 30 sec. every time and after it shut down, all the electronics would go haywire for a few minutes.

So, you might want to make sure it is the ECM before spending the money.
 
I definitely know my PCM went bad. Just looking for a RELIABLE place to get a used one - where they can reflash it. This is a DD, so I want it to run like it's supposed to - but I'm trying to avoid buying a new one if I can help it.

Any suggestions on where to get a used one?

Are there any places that rebuild them?
 
Actually....the more I research....the more I am questioning whether the ECM is actually bad. It is a 2001 XJ with manual transmission - and runs beautifully! The issue is a check engine light for O2 sensors (don't have the codes right now). All of the sensors were replaced - and the fuse for the O2 sensors keeps blowing. I need to get these codes fixed in order to pass inspection.
 
that doesn't sound like a computer problem to me. IMO, if the ecm was the culprit you'd have more symptoms than that.

Check your 02 sensor wiring and make sure it's not touching the header and melting the insulation and causing a short. I know that's a common issue.

I don't know if this would work or not, but at least to pass inspection, rent an obdII scanner from autozone (free) and clear the codes just before you take it to be inspected (like in the parking lot when you drop it off at the shop). If you're lucky the codes won't show up for a little while and you'll be able to pass the inspection. Just a thought. You could try clearing them and see how long it takes for them to come back so you know.

Otherwise, I would just make sure to check all the 02 sensor wiring and connectors. It sounds like there is a short somewhere causing the fuse to blow.
 
Thanks for the reality check on the ECM.

My codes are:
P0135
P0141
P0161
P1196 (Pending)

I tried that little trick with the pocket scanner.....but the problem is that the computer has to reset in order for it to pass. When you first erase and scan immediately after - the MIL is off.....and there are a number of sensors that are "Not Ready." Over here, you can't pass if they are "not ready" and with the MIL off. :nono:

Thanks again!!!
 
nope, 2000+ xj's have a distributorless ignition. I tried using a 2000 ecm on my 98, misfired like you wouldn't believe, but it did run, haha!

So, the answer is no. You need a 96-99 ecm.
 
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