New (used) ECU going in my LGT

I have been dealing with a bunch of random issues with my LGT ever since I got it a year ago. I bought the car with a blown engine and built it. It has always had a very rough idle and throws a random cylinder misfire code here and there. When cruising in 3rd gear at about 35MPH there was always a slight hesitation or felt like a misfire again. All three time I have had it tuned, my tuner even stated that there was some weird interference too. Finally threw a P0607 (control module performance) code and after I reset that it ran fine for a couple of days. Then all of a sudden I was leaving work 2 weeks ago and the car started right up like always. Only difference this time is that it died as soon as it fired up. Did this about 30 times before it stayed running to drive home. The last 2 weeks sitting at home I have tried to start it and all the time it just dies. I have been looking for an EC for a couple of weeks and finally found one. Thanks again MONEY. The car goes in tomorrow for the pairing with my immobilizer so I can reload my tune and hopefully have a running car again. Wish me luck fellow Subaru nuts.

Sounds terrible. Good luck!

Ready for the doctor.

Good luck with it. I hope it clears up your PITA issues.

Well, got a call from the doctor. Seems it's not a brain transplant, but a heart transplant. Turns out after swapping in my new(used) ECU, that was not the problem. They put the original ECU back in and started to track things down. Turns out it was the BIU (body integrated unit), this basically controls all the other functions on the car except the engine control functions. Part ordered and hopefully should have the car back on Monday. Kind of explains now all of the random problems. The bad BIU had an intermittent short.

BIU ties the locks/alarm/immobizer and more to the ecm. If the BIU goes, all sorts of oddities happen.

BIU ties the locks/alarm/immobizer and more to the ecm. If the BIU goes, all sorts of oddities happen.

 

 

You understated this.

 

I was wondering why I have done the seat belt chime delete about 30 times and it would NEVER stay. Kind of makes sense now why all of the random codes I was getting too.

At least I will have a couple of ECU's to try and sell to get some of the cash back.

I have had "fun" troubleshooting BIU issues and immobilizer issues in the past.

Chrysler has had the BCM (body control module) issues for years. It definitely affects driveability as well as the stupid door lock, alarm, interior light, trunk release, etc. issues. I would bet that will clear everything up.

Just an update. The ecu took out the new BIU. Now I'm looking at a new ECU and a BIU 2 more new keys (5 total at this point). The keys can only be paired once I guess. The bill went from the initial 300 to a nice round figure of 2700. They claim that the tune and the condition of the original ECU is causing the problems. New parts should be here on Monday and then the install and programming again. You do NOT even want to hear the conversations my wife has had AT me.

Just an update. The ecu took out the new BIU. Now I'm looking at a new ECU and a BIU 2 more new keys (5 total at this point). The keys can only be paired once I guess. The bill went from the initial 300 to a nice round figure of 2700. They claim that the tune and the condition of the original ECU is causing the problems. New parts should be here on Monday and then the install and programming again. You do NOT even want to hear the conversations my wife has had AT me.

 

Possible to find a used one on here or over on NASIOC? Maye if they are a matched set, you would be OK?

 

I've not changed these before, at least on Subaru's but it makes sense that if they were matched, they should work. I would check the vehicle part outs and see what you could find.

 

Sorry for your shi**y troubles. I truly hope they work out.

Subaru always blames the tune. So what is really taking out the ecm? Is there an underlying cause to its demise?

Briefly where I stand as of now.

 

Bought a used ECU and took it to dealer.

They installed it and the original problem still existed.

Put in original ECU and a new BIU, problem still came back.

Now putting in factory new ECU and BIU.

They do not want to try either of the old parts because if the power spike from either one already caused damage, then we are back to square one. Once keys have been paired with the immobilizer, they can't be paired with a new system, hence the pile of keys.

Gonna be an expensive trip to the doctor, but hopefully I will have a good as new electrical system.

Just an update.

New ECU and BIU. Car was washed and waxed and they were getting ready to call me and problem still exists.

Car starts and dies. Sometimes it will stay running, but most times it just starts and dies. The tech says he has been working on Subarus for 25 years and has never ran into this before. Now it looks like he will have to pull the BIU and ECU and trace wires at pin out locations individually to see what went wrong.

Any one else ever hear of this? Gonna be a long costly operation.

Could be almost anything. You have an issue not encountered by most (I would say less than 0.5% of owners). Ever have any rodents take up home in your car?

Could be almost anything. You have an issue not encountered by most (I would say less than 0.5% of owners). Ever have any rodents take up home in your car?

 

I know, it kind of sucks, but I still like my car. Could have had rodents. The car sat on a lot for 2 years before I got it with a blown engine. The battery was dead as road kill when I picked it up. Who knows how many time it was jumped and maybe a power spike or two.

Check your grounds ? mainly the one by the throttle body where your engine harness grounds too.

Exorcism?

I know, it kind of sucks, but I still like my car. Could have had rodents. The car sat on a lot for 2 years before I got it with a blown engine. The battery was dead as road kill when I picked it up. Who knows how many time it was jumped and maybe a power spike or two.

 

That might explain some of it. With a car that sat that long and has a storied history, it does not surprise me that there is an odd electrical issue now (especially with my experiences with how "touchy" the systems can be).

 

It could be a ground, a short, a voltage drop or spike, a previous repair using wire of the incorrect size/power factor/impedance. It could be... :spin:

Got to be wiring. I had a different BIU connected to my car number of times when I was fixing my illumination issue, and nothing went wrong. I couldn't run the car since I didn't pair ECU and BIU. You already went through various ECU and BIU, wiring is the only thing left...

 

Good luck.

Got a call from the Subaru doctor. Looks like they have the problem isolated to the instrument cluster. I get my car back tomorrow. Does anyone know if the cluster somehow need to be "paired" or programmed, or can I start looking for a replacement and just plug and play. I am OOOHHHHH so ready to PLAY, it's been 7 weeks.

Picked up the car. After a 20+ mile drive home , all seems well and right with the world again. Seems to run smoother than it ever has since I have owned it. Bill for the repair sucked, but I at least have 3 ECU's and @ BIU's I can sell to try and recapture some of my loss.

What did they say was the final issue?

 

Sounds like you paid for a lot of their mis-diagnosis

sounds like a flood vehicle