Originally Posted by The_Maniac

- TPMS - To the best of my knowledge, in this generation Monte, GM did not use TPMS sensors in the wheels. It's a calculation based on the wheel rotation from the wheel speed sensor (same sensor the ABS system uses). I checked this info out for my '04 Monte when I was getting new wheels and found no such evidence in the shop manual to any sensor in the wheel (like other cars use). It could be a simple enough matter that he needs to verify all wheels are at the correct pressure and then reset the TPMS system (easiest way is through the interface in the factory radio).
- Low Coolant - These cars have a coolant level sensor in the radiator (towards the top of the radiator). Many have complained of the sensor failing. You can disconnect the sensor and the light goes off. Better option is replacing it. I've never had to replace one, but as I understand, it's not too difficult to do.
And now for the BIGGEST issue:
- Air Bag Light - As I understand, to read the air bag computer and find out why the light is on, I believe you may need a GM TechII scan tool (a standard ODB-II scan tool is not equipped to read the air bag light). I've known that light to go on if an impact sensor has failed or if the clock spring in the wheel has been damaged, so it standard to reason, if an air bag was deployed and he did the DIY repair road and did not replace it AND have the air bag computer replaced/reprogrammed/reset that this light was on.
This is the problem that concerns me the MOST and would be the high chance to "walk away". Here's why:
1 - These cars are sadly at the age/mileage in most cases that if a small accident occurs that deployed the air bag, insurance companies total them (you could have a $300 body repair, but the air bag service jacks the cost up). As a result, a lot of great cars that need a minor repair from a fender bender get totaled. We've seen this happen before on this forum too.
2 - If the clock spring is the issue, you can simply replace it, light goes off. I believe the same is with an impact sensor. I was always under the impression that the computer must be reset with a GM Tech II. I do not see this in the shop book for these cars (so that may be a condition with newer cars).
3 - Looking at the shop book, GM tells you in the event of a deployment a bunch of things to inspect and replaced (some of it includes damaged/burnt/melted connectors).

I know some people have their claims about why they don't like air bags. I've been fortunate to never have one go off (granted, I was rear ended hard in a '93 Buick Century with a bag, I'm surprised it did not deploy). So if working air bags are not an issue, then all this may not concern you. Or you may plan on hitting junk yards for salvage parts. Warning about that. I know a guy who used to do air bag service years ago. He recommends against salvage air bag parts because you have no way to test their condition and you would never know if you put bad parts in a car (I've argued "but what about cars that got sent to the yard that had nothing to do with a collision" and his advice is still, stay away).
But regardless your opinion on the air bag system, here is another reason I would be concerned:
- You have been told the accident was bad enough the door needed replaced. What other damage is on the car. These cars do NOT have a full frame (they are unibody cars). Is the floor pan damaged, rocker panel (under the ground fx) bent? Those pertain to the body itself. Does the replaced door open and shut properly? Are the various body gaps on the door correct and lined up? Are the various body lines true? If there are issues with those items, they may suggest further repairs are needed.

FYI - All this is coming from a guy that resurrected an '84 Camaro after wrapping the rear quarter around a telephone pole. Yes, the car CAN be made right even if it's not right. But I already owned the Camaro, so what I did was all on me, in this case you don't own the Monte.

Sorry for writing a novel. The only issues I have pertain to the accident that deployed the air bag. Are there signs of additional damage and cost to repair the air bag system. If you can, try to get the car to a GM dealer, ask them to scan the Air Bag computer and possibly an estimate for servicing. But also look in and around and under the car for signs of additional damage.
Lastly, if you still want to go for it, make sure to check KBB.com for values AND look around at other comparable cars that may not need the work to fix. If the cost of repairs outweigh the KBB value of the car (or other Monte's in your area), NO DEAL!