2005 Deville Air Bag Light On

[KHE]

My '05 Deville had the airbag light on and a SDM B0101 CURRENT code.  It just happened one day a few weeks ago when I backed it out of the garage to wash it.  I store it winters and have put less than 1000 miles on it this driving season.

The shop manual defined the code as "front impact sensor discard".  The manual concentrated on the SDM B0100 which is an opened sensor and there was not much information on the B0101 code.  I figured the sensor was shot but the retail price of the sensor is $220.00 - I decided to remove the sensor from my wife's 2004 Deville and install it in the '05 to see if the code went away.  The sensor is mounted on a crossmember behind the radiator - the splash shield needs to be removed to access the bolt.  It wouldn't budge so I abandoned the idea - if something went wrong and the sensor got damaged, I'd be buying two of them... 

I decided to take the sensor out of my car and plug it into the '04 to see if the SDM B0101 code set on the '04.  No luck - I broke my T-30 torx driver socket.  I thought if I unplugged the sensor and the SDM B0101 changed to history and the SDM B0100 code set, there was a good chance the sensor was bad.  Sure enough that is what happened.

I used to order parts from Brasington Cadillac in Florida - great prices and the parts were delivered to my door in three days.  They became Palm Chevrolet Cadillac and are now Davis Chevrolet Cadillac.  Long story short - they don't discount parts anymore.  I ordered one from gmpartsgiant.com for $159.00.  It arrived Monday and I immediately noticed  the screw was a left hand thread!  The service manual made no mention of that!  I attempted to remove the screw from the old sensor but it would not budge - even after removing the radiator support cover and spraying the exposed threads with penetrating oil.

I then decided to drill out the screw using a 1/4" drill bit at a low speed to not work-harden the screw.  I got just past the bottom of the torx feature and very few chips would generate.  That screw was hard as rock.  I didn't have a cobalt drill bit so I kept drilling, keeping the drill bit lubed with cutting oil.  I got to a point where I was able to get a small cold chisel in there and gave it a whack with a ball peen hammer and the head popped off and I was able to remove the old sensor.  A cobalt drill would have made the job much easier.

I lubed the screw that came with the new sensor with anti-seize and installed the new sensor and no more code/airbag light.

I inspected the old sensor and could not see any cracks or any evidence of water intrusion.  I sawed it open and saw a small circuit board - something must've failed on the circuit board.

I thought I'd post this as there was very little information on the various forums about the B0101 code and certainly no mention that the mounting screw had left hand threads.  If anyone has to change out the sensor on their car, it is a left hand thread so turn it clockwise to remove it.  If it won't budge, buy a 1/4" cobalt drill bit and drill the head down to the body of the screw.  The cobalt drill bit will make the job much easier.

[Logan]

My first car had left hand lug nuts on one side of the car.

Anyway....the electronic GM ESI service manual does mention the sensor has left hand threads. 

[KHE]

Even if I would have known the screw had left hand threads, it wouldn't budge.  It was seized into the bushing of the sensor which was strange since the car doesn't see road salt.  I wonder what the failure mode is on these sensor?  Mine was most likely some component on the circuit board.

I would bet the seizure of those screws in the sensor is the reason a new screw is included with the sensor.  The new one in my car has anti-seize on the threads.  Hopefully, I don't need to do the job again but if I do, it will be much easier.

[sonjaab]

Logan:"My first car had left hand lug nuts on one side of the car."

Was it a Mopar car?

[rockfangd]

Glad you posted this. 

I have done tons of these on GMs.

I use the torx on the top side going forward to loosen the bolt. Only has to be loosened enough to slide it back, then it drops out.

I use a reverse torx to do the install From the sensor side you turn it forward to snug it. I have had nightmare ones.

The bolt and sleeve rusts and splits the sensor in half sometimes. I always coat the new one with grease.

Glad it resolved your code. I find that sensor throws multiple different codes among GM models.

So far most common years are 2004- 2015, same is used on the newer ones too, just have not rusted yet.

Wish the sensor was a little cheaper

[Logan]

8 hours ago, sonjaab said:

Logan:"My first car had left hand lug nuts on one side of the car."

Was it a Mopar car?

'63 Oldsmobile