posted by
someone claiming to be 93-940 & 99-V70
on
Thu Mar 18 00:49 CST 2004 [ RELATED]
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Bad news for me. After Volvo diagnosed the SRS light and 1-1-2 code, and inspected the wiring from the keyless remote installation, they said that the installer did it correctly. The fault is internal to the crash control unit, and not caused by the keyless remote installation. So the $1,229 plus installation is mine ($1,478 installed). I did get them to come down $100, then I have a coupon from Volvo for $100, but that is still $1,278.
Semi good news for me. Calling around I did find a family owned Volvo only repair shop (Southwest Auto - formerlly called Just Volvo) that has used ones for about $400.
Guess where I'm going?
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Went to Southwest Auto in Dallas with the intention of having them install a used crash sensor for a few hundred $. They first wanted to check it out. They checked fittings/wires, and got the code readout. They then reset the code. They test drove it 3 times on bumpy roads, turning it off then on each time so the computer would go through the SRS check each time) and it never came back on. I have driven it twice without it coming on.
Their tech said 9 out of 10 times some fluke makes it go on, and once it is reset it never comes on again. Said there is a chance that it has a weak component (maybe the backup power capacitor) that was affected by the keyless remote install (battery disconnected for over 5 hours, or they temporarily disconnected the harness, etc.). Could have just been a very hard jolt that set it off (but there was not other input required to set off the bag), or who knows what.
One important thing he said was that they always read the codes three times before resetting them. He said often they will not reset after just one, or even two readings.
Sorry Spook, we will not have autopsy photos, yet at least.
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Dear SJP,
Good p.m. Sorry?? I am DELIGHTED the fault was purged.
Glad to learn it was transient.
It would, of course, be interesting to know if a weak capacitor is actually at the root of this problem.
In any case thanks for reporting on how the problem was cured.
Yours faithfully,
spook
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Sounds like an honest, savvy place to go. Some shops would have just replaced the sensor with no questions asked. I once had a mechanic like that but he retired, darn it!
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I should add that, as we discussed, even disconnecting the battery for a long period of time didn't reset the code. We posited that it may be due to the capacitor in the SRS crash sensor retaining some juice.
Also, in the past I've had to go thru the code resetting procedure several times in order to get the codes for various problems reset. So the message here is that crash sensors rarely fail, and when you get a code keep trying to reset it, and don't rely on disconnecting the battery to reset the code.
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Thanks.
Pathetic that we work in the same building but rely on Email to converse.
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I have a used crash sensor to sell cheap. Message me if you are interested.
--
john
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Go with a used unit: my brother did this (same problem) and it worked fine.
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Dear SJP,
May this find you well. Sorry to hear of this. Might I suggest you apply the method I suggested, to see if this internal fault will clear itself?
That is, disconnect the negative battery cable clamp from the terminal, and let the car sit for an hour. If the fault self-clears, you're fine. If not, you can get it replaced with a used unit.
The only side-effect of doing this, is that you'll have to reset the security code on your radio. If you don't have that code, the dealer will give it to you if you supply your car's VIN.
By the way, unless you have to give up the failed unit in exchange for a working unit, I'd like to have the failed unit. I've never had one of these apart. Let me know. Of course, I'll cover the shipping costs, assuming you're somewhere in North America.
Yours faithfully,
spook
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posted by
someone claiming to be 93-940 & 99-V70
on
Thu Mar 18 02:26 CST 2004 [ RELATED]
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Volvo said the tried the battery disconnect test. I will try it myself.
I may not be able to send you the unit as my Volvo/Brickboard friend at work already asked for the same. Maybe we can send you the pieces later.
Thanks,
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I'm his friend - we plan to do a post mortem on the patient. We may post the autopsy results on the board.
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Dear SJP,
Good p.m. Nothing would please me more than to learn that your airbag sensor unit has "re-set" itself.
I suspect that the wiring harness work was done without the battery's negative cable clamp having been removed from the terminal and isolated (put in a plastic bag). That would have isolated the sensor, and protected it from any harm.
When the steering column wiring was cut, to splice in the keyless remote, the power flow disruption - or possibly an inadvertent and brief short-to-ground - triggered the sensor fault reading.
However Volvo tried to get the sensor to re-set itself, you have nothing to lose by trying again (assuming you have or can get the radio security access code).
Please post about the outcome.
Yours faithfully,
spook
p.s. If your colleague is an engineer or electronics repair technician, I'd be interested to know the results of any post-mortem of the old sensor.
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posted by
someone claiming to be 93-940 & 99-V70
on
Thu Mar 18 06:44 CST 2004 [ RELATED]
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Tried the battery disconnect for about 2-1/2 hours. No good, still the light and code 1-1-2. It is at Southwest Auto. They are going to see if they can reset it, if not a used one will be put in.
We are both engineers, though not electrical (chemical and petroleum). We are planning on posting some autopsy photos.
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Dear SJP and jkordzi,
Good p.m. Super! With so much engineering savvy, if the fault can be found, you'll find it.
I'd be especially interested to know if something "got fried", i.e., if there are obvious signs of overload.
I wonder if there could be a fuse or a relay inside that box, which if replaced, would restore the unit to working order.
I await further. Thanks in advance for your report.
Yours faithfully,
spook
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posted by
someone claiming to be charles
on
Thu Mar 18 01:29 CST 2004 [ RELATED]
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spook is right.sometimes out of the blue you get a code.reset it will do the trick.i did mine 1 year ago and still off.good luck.
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