In the first video "Buick LeSabre: Customer Replaced ECM Now A No Start, No Lights, NO NOTHIN!" we had a look at this Lesabre that was towed in after the customer replaced his own ECM causing a no start. After we got the vehicle up and running it was obvious that it needed some work to fix the original complaint. We had our suspicions about a plugged exhaust, so let's see if our hunch was correct! -Enjoy!
If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE:
CHECK OUT OUR "SMA SWAG" STORE! Go on Teespring and get your very own SMA merch!
If you don't like Patreon feel free to use the "PayPal Me" link:
The South Main Auto Amazon Store:
AES Wave Automotive Diagnostic Tools:
Thank you for all the continuing support!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained

50 thoughts on “Buick lesabre: customer replaced ecm / no start : the final diagnosis”
  1. Avataaar/Circle Created with python_avatars Xtammy5800 says:

    These cars are designed so you cannot over rev them…

  2. Avataaar/Circle Created with python_avatars Carlton Wilson says:

    Wonderful to see a serious auto mechanic/ technician at work using REAL diagnostic skills. You sir are a real professional, I hope you have some younger techs learning from you too.
    BTW I watched the video before this one when this car was stuck in the parking lot, impressive. 👍🏽

  3. Avataaar/Circle Created with python_avatars MasterG753 says:

    Subbed. and I'm not a mech but this was more than interesting.

  4. Avataaar/Circle Created with python_avatars Sandra Tyner says:


  5. Avataaar/Circle Created with python_avatars Clare Ravenwood says:

    Had a bad starter, replaced it with a rebuilt one that was nearly as bad. Got it tested, bad rebuild right out of the box, replaced under warranty, no more problems so just because it's new doesn't mean it's good.

  6. Avataaar/Circle Created with python_avatars Shane Harrison says:

    Yeah some run hot some dont and that doesn't always work but I can see thse was has it's good points but I believe the way you did it is closer to right

  7. Avataaar/Circle Created with python_avatars Jim Vet says:

    good job, one of the comments reminded of a neighbor of mine something near 40
    years back, his work truck, he did land scaping, did nice work, he never mentioned anything to me, I had noted he been messing around under the hood, the short of it, it needed an alternator, no problem back then easy fix, he pulled the starter took it in and tells the clerk
    I like a alternator, OK and what do want to do with this. the guy new right away he had no clue .
    His wife got a hold of me I put things back right and got the alternator.

  8. Avataaar/Circle Created with python_avatars HighRange Mike says:

    I’m having issues with my 05 Buick lesabre. I’ve been told by a local shop it’s the timing chain. I’m not so sure that it’s my timing chain issue but rather an exhaust/catalytic converter issue..

  9. Avataaar/Circle Created with python_avatars Makla says:

    How would you plug the hole for the vacuum gauge after the test (if the cat was to be re used)?

  10. Avataaar/Circle Created with python_avatars BEAVIS says:

    What I wouldn’t do to have him as my neighbor.

  11. Avataaar/Circle Created with python_avatars MrHeavychevy86 says:

    do a converter delete

  12. Avataaar/Circle Created with python_avatars Mark from [fordmustang98guy] says:

    That’s the 2003 Buick LeSabre

  13. Avataaar/Circle Created with python_avatars James Holbrook says:

    I think YouTube recomended this to me after i was looking for starting and or grounds because my moms car was not starting I was thinking it was a ground but there was no nut on the positive cable

  14. Avataaar/Circle Created with python_avatars Daniel Roberts says:

    If you put a pressure reliever in the back of the cat and test it. Wouldn't that give you a more accurate reading than allowing pressure to escape from the front of the cat? Does my question make sense?

  15. Avataaar/Circle Created with python_avatars walkingman says:

    Nothing like having knowledge, common sense and good test equipment.

  16. Avataaar/Circle Created with python_avatars fictional25m says:

    I worked for years in many shops some hired right out of voc I know they have to learn but exposing bad mechanics can be a good thing if no one checks there work or calls them out..
    ive seen simple things turn into expensive nightmares and multi bay shops pass on bad diagnostics onto the customer "they find a way to blame shift it back to the customer" sometimes parts chasing is done on purpose by multi-bay name brand shops I left the industry because of it even had bad mechanics blame shift onto other mechanics in the same shop
    I got tired of the crap working in those types of shops because if the bad mechanics can get away with pushing high flat rate hours on unneeded parts and the managers let customers get ripped off its just not right..i exposed the bad shops by name because if not who will..and the small shops that do honest work don't get recognition so expose them by name…

  17. Avataaar/Circle Created with python_avatars A Team says:

    ooh I have nothing better to do than wait around for people to pick up their part and then wait for them to bring back a new part, after they dropped it, or to find out they got the wrong part,

  18. Avataaar/Circle Created with python_avatars GhostDragon says:

    Nice video. Gm solenoids have a large copper contact washer inside, only half of it is used, I have fixed several by just spinning the washer 180` to the unused half of the contact, presto, just like new 🙂

  19. Avataaar/Circle Created with python_avatars Hola! torquewrench jeff says:


  20. Avataaar/Circle Created with python_avatars Hola! torquewrench jeff says:

    ok time for me to add my two cents here. So ok my assesment is somebody had been doing repairs on this way before it came to Mr. O or Eric lol. Anyways id assume that the same person that tried to force wrong computer in is the same person who put the starter in. I run a mobile repair business and I see mistakes thathave been made in the past which have costed some customers into the thousands. Before Craigslist made its debut my business made roughly 5 times the profit and 5 times the amount of business. There are inexperienced mechanics out there stripping bolts and crossthreading them at an alarming rate. We all as wrenchers have done it but than we replace or repair bolts before we conclude repairs whereas many of these guys don't whichis messed up. LAST WEEK I THOUGHT ID HAD FINALLY SEEN IT ALL WHEN I HAD GONE TO A REPAIR WHERE SOMEONE HAD STUCK A WOODEN PEG INTO A FRONT CONTROL ARM BOLT HOLE RATHER THAN THE BOLT. THE CUSTOMER DIDN'T AND STIL DOESN'T REALIZE HOW CLOSE THEY CAME TO DEATH. WHAT IF THIS PERSON HAD GONE ON THE HWY INSTEAD OF CALLING ME BECAUSE THEY MISTRUSTED THE GUY WHO PUT THE CONTROL ARM IN BECAUSE THE MECHANIC DIDNT HAVE BASIC TOOLS. THERE IS NO EXCUSE. Anyways on the repair Eric is doing id bet whoever put the starter i to begin with put nut on starter hand tight than forgot to tighten or crossthreaded the nut . There is no reason to crank that nut down and brand new starters get ruined for that reason. Not to mention the next guy goes to loosen the nut 5 years down the road and the whole works spins+ breaks off.

  21. Avataaar/Circle Created with python_avatars Dmanuel Flores says:

    You can also check it at night without making holes. Turn it on and run it a while, then check under the car in the dark and see if you have a slight glow from the heat. But its not the best way to check.

  22. Avataaar/Circle Created with python_avatars Dave Williams says:

    I appreciate this video from a first hand experience of punishing myself. My '04 Silverado needed a heater core, Which as you may know requires Dashboard removal! Quotes exceeding the trucks value. So of course, I decided to do it myself. Removing the dash requires considerable wiring disconnects. This all SEEMED simple enough, just time consuming! Well, after completion, I had a NO crank situation and power loss to many other random circuits. All fuses good!I had no choice but to retrace ALL my steps and see where I'd gone wrong. So after bringing her back to Stage 1, I found a "smushed" main body connector just under and next to the steering column. This connector used a type of "swing over" locking clamp that compresses the two together forcibly but with little effort. and it was obvious that the pins inside had "mooshed" and caused all the issues. Wires being so short, times and tempers matching! I decided to remove the very nearby main cabin fuse panel and get more slack to work on this connector and it's pins. At this point the $2200 quote for this heater core job seemed like a bargain! However, I was WAY too deep and HAD to complete this on my own. MORAL of story, Bring it in, It ain't just "Nuts and bolts" It's a whole lot of knowledge, that most of us don't have. But think we do! Thanks Eric for showing us exactly this with this video series. CARS aren't simple anymore! This Ain't my moms '69 Nova!

  23. Avataaar/Circle Created with python_avatars Chris Chiampo says:

    Damn Did Anyone Else See All The Wheel Weights On That Driver Side Tire as Eric Panned Down From The Loose Starter Terminal Wire 😳😮😮😲

  24. Avataaar/Circle Created with python_avatars Ivan Psimer says:

    Ive had a few vehicles that we run hot wires into the cabin to cross over the starter. Was cheaper and easier than getting a replacement, and worked just as well. Only downside is it made your car look stolen hahaha

  25. Avataaar/Circle Created with python_avatars Cindy Tepper says:

    Trans went bad in my truck years ago. I was at the shop and it was late so I grabbed a dealer plate and put it on a ford we towed in and the customer gave it to us. I knew it ran and drove, everything worked so I figured it was my ride home. It was good until I got on the highway and it wouldn't break 25. I was just about home and a cop pulled me over for going so slow. It had gotten worse and I was down to like 15. He told me he thought for sure I was drunk. That was a plugged up cat. We ummm "fixed" the cat and used it at the shop for a parts runner for years

  26. Avataaar/Circle Created with python_avatars DeadKoby says:

    Your troubleshooting style is very practical. This reminds me of my Dad's style. Rather than go get the test machines galore, we look listen and sense where the issues would be first. Darn Buick is a mess.

  27. Avataaar/Circle Created with python_avatars deseehc says:

    What ir temp gun are you using.

  28. Avataaar/Circle Created with python_avatars Eddie 1967 says:

    How about and Inspection camera in the inlet hole you drilled. And see if it's melted solid.

  29. Avataaar/Circle Created with python_avatars Curtis Lee says:

    Too many adds!!! 👎

  30. Avataaar/Circle Created with python_avatars Tyrone Cocobeach says:

    wonder if the original starter was good…did you ever try and bench test it before replacing?…Curious if you are ASE certified?

  31. Avataaar/Circle Created with python_avatars Jesse C says:

    My favorite. "It's just the gas cap". lol!

  32. Avataaar/Circle Created with python_avatars topher says:

    Such a basket case jeeeze. Bad fuse, screwed up ecu connector, loose starter, restricted exhaust

  33. Avataaar/Circle Created with python_avatars Sky Tiger says:

    Temp is what I tried 100 times now I know better but the engine being choked was the best evidence if I was guessing.

  34. Avataaar/Circle Created with python_avatars Kelly t says:

    Awesome job on chabacled car

  35. Avataaar/Circle Created with python_avatars rehab joe buffet says:

    As far as dependable cheap cars go these Buicks seem pretty bulletproof! I got one for free that had previously been thoroughly beat into the ground! I drove it for two years without issue until I donated it to charity! When I got it it had over 200k on it, ripped up interior, electric windows didn't work and the trunk wouldn't latch but it never gave me any trouble at all! I gave it away in the exact condition In which got it!

  36. Avataaar/Circle Created with python_avatars Cody Call says:

    Had a ford v10 3 valve motor home that wouldn’t run. Had it towed in. Scanned for codes and there was dozens. Got it to fire and heard weird hissing noises crawled underneath and seen the gasket into the cat had a hole and exhaust was blowing through. Unbolted the cat from the exhaust and it fired right up.

  37. Avataaar/Circle Created with python_avatars Ryan Dickerson says:

    The best way I have found to check for exhaust backpressure is to find a Oxygen sensor threaded adaptor (most have same thread pitch) to a hose nipple, and then vaccum line to a pressure gauge. Simply remove the upstream O2 sensor and install this finger tight. No drilling required. Now I will say, that's what we do in the South, where we don't have to worry much about rust. O2 sensor removal might be a bit more tricky in the rust belt.

  38. Avataaar/Circle Created with python_avatars Limu Emu says:

    really good info, thanks

  39. Avataaar/Circle Created with python_avatars Tim Nelson says:

    Man you know its a back woods hillbilly with that steering wheel cover

  40. Avataaar/Circle Created with python_avatars mark p says:

    Isn't there an oxygen sensor on both sides of the converter? It should light up the dash light if there's too much of a differential from one side to the other indicating a bad converter.

  41. Avataaar/Circle Created with python_avatars Odin Smith says:

    Do you even need a cat converter?