Churchill

This is not the typical post on this, I think. I don't have trouble connecting to the airbag system. The problem is the Durametric won't clear the warning light, which has been lit since I swapped out a steering wheel a while back. I'm new to the Durametric, but seems to me there are two possible culprits here:

1) I can't clear the code because there's now a deeper problem than the light being tripped during the steering wheel switch. Maybe since then the control module went bad or there's another problem.

2) The Durametric is erroneously reading codes. In support of this theory, I'm getting varying trouble codes depending on when I check for faults and what part of the Durametric system I access the airbag system from. See screenshots below. The consistent ones across all the tests are "airbag warning light" and "belt tensioner, driver's" with "supply voltage" regularly appearing.

My car is a late '96 build with a three-spoke 996 airbag wheel. My car still has, to my knowledge, the stock airbag module (I've owned the car 12 years and never touched it, and there's no service record of it being done).

Help!

pp000830

There has been a new version of Durametric released to eliminate some erroneous code reporting.
Verify you are running the latest version and if not uninstall the version you presently have on your laptop and install the latest version from the Durametric web site.
The code can only be cleared if it is a non-deployment CEL, the way you know this is the airbag warning light goes out after a few minutes with the ignition on. If the airbag light stays on and doesn't go out the system has a deployment fault that I understand can't be cleared.
Also be aware the airbag on a 993 may be the same revision as on the earlier 964 or the later 996 so consider navigating the Durametric program to those models and see if clearing the airbag code from there works for you.

Good luck with this,
Andy

Churchill

Thanks Andy. I have the always-on airbag light. I've tried navigating to the system through the 996 and 964 parts of Durametric, but it won't connect -- only connects through 993.

911PERVY

My guess would be the slip ring if this only happened after removing, they are very easily damaged, you need to try and borrow a know good one.

pp000830

Now you get to learn from my folly:
There is a specific procedure to position the airbag units contact rotation unit under the steering wheel. If not done when replacing the wheel one can damage the contact unit by clocking the steering wheel past the units range of rotation.
Flipping the wheel around I broke the airbag’s rotation unit’s rotation alignment pins that engage it to the back of the steering wheel, I ended up repairing the pins.

If your issue is a damaged contact unit you may need to replace it or repair it. Then re-clock the airbag contact unit according to the directions printed on the unit or in the shop manual. When re-clocking the airbag contact unit a good trick is to remove the grossly over-engineered small metal spring loaded “Rotation Lock” on the face of the unit and just use a piece of electrical tape. The rotation lock tends to fail anyway when used and in some cases snaps off and jambs up things. If using the tape method thread the tape like a tail through the middle of the steering wheel to be pulled out by its end. Once the steering wheel is in place, with the contact unit clocked correctly and the engagement pins are in their slots at 12 & 6 o’clock just pull the tape out through the wheel.

Before you loosen the steering wheel’s hold-down nut to get at the contact unit don’t forget to mark the steering wheel’s position to the top of the steering shaft so your steering wheel can be put on back on its spline where it was (strait).

Warning: Before doing this procedure disconnect the negative terminal on the battery. When unplugging the steering wheel airbag unit from the steering wheel do not reattach the battery until you have reconnected the airbag unit otherwise you will cause an airbag fault (warning light) that will need to be cleared by using an OBDC Reader such as Durametric or having the dealer do the same.
Andy

JasonAndreas

...

Churchill

Thanks again Andy. Jason I'm happy to take suggestions, even if you're not 100% certain...

Part of what I don't understand is why the "airbag warning light" is itself listed as a fault. Isn't the warning light tripped when something else is faulty?

samurai_k

Hello Churchill,

In regards to the airbag light fault, you could have potentially a bad clock spring.



Mine failed and the horn stopped working. The horn and the airbag circuit is routed through the clock spring. If it fails you will have an open circuit on either the horn or airbag. In the case of an open circuit on the airbag it will cause a fault. Simple test is to pull out the clock spring and do a continuity test...

Good luck and happy holidays!

ToreB

The airbag warning light bulb is supervised by the control unit. If the bulb is blown, the according fault code is triggered, and the warning light is (supposed to be) lit.
The most probable cause for this particular fault is intermittent contact with the bulb, either in the bulb holder, or the instrument connector. This can most often be corrected by pulling the connector off and on, or turning the bulb in it socket a couple of times.

By the way, none of the airbag control unit fault codes can be deleted by removing the battery power from the car.
Cheers,
Tore

nine9six

Disconnecting the negative battery terminal is a precautionary measure only, and all of the work discussed above can be performed with the battery connected, just as long as the key is not turned to the ACC position, thus energizing the cars entire electrical system beyond that of the maintenence system; therefore throwing an airbag light from not being plugged in.

Many who upgrade to the 3 spoke wheel, forget about properly aligning the steering wheel prior to swapping and make the mistake turning the key on, to unlock the steering column in order to adjust the clocking of the steering wheel.

FWIW, I have never been able to reset the airbag light using the Durametric diagnostic tool, (Enthusiast version with the later cable and latest software). This and the bevy of erroneous error codes are enough for me to steer clear of ever using the tool again.

A Bosch KTS300/301 (Hammer), Bosch KTS520 (PST2), or a Bosch KTS650 (PIWIS), are the propper tools for the job, IMHO.

samurai_k

I have a durametric and it has been able to reset my airbag faults caused by the mistake you described above when I didn't know any better changing my steering wheel out.

I did upgrade the firmware and software to the latest per Andy's suggestion above.

@Churchill, do you still have your old airbag? Another quick test is to clear the codes/faults, remove the 996 airbag and install your old one. If you don't have one you can use a resistor. If you turn on your car and the big red exclamation point appears again then at least you know the airbag is good and could be the light bulb as tore mentioned or the clock spring? Or something else...?

Happy holidays

Churchill

I'll be a monkey's uncle but it was the airbag light. All credit to Tore. Changed the bulb and the warning light is gone. It must have burned out at some point after I swapped out steering wheels, making me think it was being caused by the airbag swap. Didn't know that little instrument bulb would trip the warning light. Lesson learned. Thanks again Tore.

911PERVY

I thought lamp was lit? What bulb was blown?

Churchill

I was getting the master warning light, the big red exclamation point. The airbag light that was burned out is at the ~2 o'clock position on the clock. One of these:

https://www.autohausaz.com/pn/13103626-JA-96464192000

nine9six

... I thought it was the airbag light as well, based upon the contents of the OP.

A photo of the dash, in addition to the Durametric screen shots might have been more clear as to the potential issue but as usual, Tore is da man!