airbag sensor, alternator

[GTOger]

Hey fellas,
I put the car in the shop to get a couple things tweaked.

1: Infl Rest and passenger seat-belt light stay on. I diagnosed as a Code 26, faulty sensor RF. Most common issue seems to be faulty ground between chassis and sensor, but the shop says that checks out OK. Is there anything else I ought to point them towards? If its a bad sensor, I'm told they're discontinued... but I imagine I could likely find one if I looked around.

2: Squeaky belt. The tensioner was the main culprit, and I'm replacing that with a spare I had bought with the car. They're saying the alternator also is squeaking. I understand replacing the alternator is a big ordeal to replace on the LT5, is that so? Any guesses on what I might expect to pay for a special LT5 alternator?

Thanks guys. Trying to figure out if I should have them spend more hours on it or button it up and I'll tackle stuff later. I don't consider either of the above to be major driveability issues.

[jrd1990zr1]

My $0.02

If it is setting code 26 it is most likely a ground issue. Did they actually clean the contact area and add a star washer to each bolt, or? The sensor is right under the AC drain and prone to rusting the ground connection.

You can test the sensor using the procedure in the FSM. I will almost bet the shop could not clear the code 26 that is why is is still in the DERM. Clearing the code is a PITA and may take many trys. If you diagnosed it try clearing it yourself.

You can remove the alternator without pulling the plenum. Not an easy job. Last time I pulled my plenum I had new bearings put in the alternator by a friend. Cost was about $20.00. If your alternator is an original don't let them use it as a core. Keep it and have it rebuilt as a spare. In my opinion unless you are planning a long trip, pull the plenum yourself and send your alternator out for a rebuild.

Good luck,

[GTOger]

Thanks jrd1990zr1. For giggles... let's say I am planning a long trip in a couple weeks. Dallas > Las Vegas > Dallas. Now what do you think about the alternator?

[jrd1990zr1]

If it was me, I would pull the plenum and alternator (one night after work), have new bearings put in the alternator and reinstall. Or pick up a rebuilt and install.

I wouldn't worry about the airbag system. I think I read (in the GM service bulletin) the system functions even with the code in the system.

Wish I was going to Vegas!!!!!

[tomtom72]

I'll almost bet that the DTC for the INFLREST light couldn't be cleared. The timing between grounding and un-grounding the terminal is 1 sec. +/- 0.5 sec. according to the FSM.

I made a grounding tool using a door bell button & used the elapsed timer in the radio as a stop watch.....got it the first time after trying enough times to make me want to burn the car!

Also, on the sensor reground procedure, the right sensor is difficult to get at unless you remove the washer bottle. You can go in thru the rear of the wheel well if you remove the panel...but it's still no room to swing a 1/4" ratchet even! You may have to do this yourself to make sure it's done right. I'd do both sensors over if it was me....just saying & not maligning the shop either as the right side is a pain in the butt & clearing the DTC without a Tech1A is another pain.


Tom

[GTOger]

OK, the shop did to the sensor correctly (yeah, it was a pita!) but wasn't able to get the code cleared. I may give it another shot using the clearing procedure... if I can find it. I wish those Tech1s were easier to come by. I'd almost just go ahead and get one.

Good news on the alternator: bearing is FINE! Tensioner pully got replaced, no more resistance, no more squeak. Also put a new belt on, even though the old one had less than 500 miles on it. I'll keep the old one in the car for the trip. Just in case.

[jrd1990zr1]

I use one of Gordon Killebrew's diagnostic plugs and count out loud. Takes a number of times but it does work. If you can not find the procedure in the FSM let me know I might be able to email a copy or at least send you the page. I know it is in the front of the SIR section.

I am interested in what Tom built. Sounds like he has the perfect tool. Hey Tom could you post a photo?

[tomtom72]

Here you go guys!








it's a door bell button, a 'gator clip for grounding, and some doubled up phone wire to hit the ALDL pins.

Just have to remember that when you push the button you are grounding the circuit!

[ittlfly]

Good news it wasn't the alternator causing the problem.

FWIW (incase you have to do the job in the future) I just had my alternator rebuilt. I didn't have to pull the plenum to remove it. It's a straight forward job (with some help from some Forum members). The best advise is to just take your time. You'll get to bond with your car and save some money too.

[jrd1990zr1]

Originally Posted by tomtom72

Here you go guys!








it's a door bell button, a 'gator clip for grounding, and some doubled up phone wire to hit the ALDL pins.

Just have to remember that when you push the button you are grounding the circuit!

Nice Tom!

If we could get one of the grounding plugs from Gordon and incorporate the button into the circuit clearing codes would almost (HA!!) be fool proof. Thanks for sharing!!