[Diy_efi] RE: Reset ECM after replacing airbag? (Ken)

WopOnTour wopontour
Wed Apr 20 18:20:03 UTC 2005


I wouldnt advise this.
During the manufacturing of airbag components, on-line testing and quality control procedures are performed in controlled conditions that assure the safety of the individual performing the tests. 
But I can tell you that ALL of the major automotive manufacturer's published service procedures, specifically advise to NEVER connect an ohmeter or any other "self-powered" equipment across the squib/initiator terminals of an airbag deployement device. True,it is highly unlikey an inadvertent deployement would occur, due to the high impedance levels of most modern DVOMs. But this type of testing is considered an unneccessary risk that places the technican in a comprimised position, and in the line-of-fire should an accidental deployment occur.For that reason alternative and absolutely safe testing procedures have developed. One example is the use of a suitable scan tool that allows the techncian to observe the air bag module's calculated value of the initiator resistance, that is based on it's voltage drop as a micro-ampre curret is applied as part of the module's built in test equipment. Another common technique used by the manufacturers is the installation of a substitute fixed resistor of the identical value of the initiator and observe the system reaction or observed change in the scan tool data. So like I said anyone attempting to repair an airbag system on their own can do what they want, test in any fashion they feel neccessary. However should some unfortunate incident occur (now or in the future), the only recourse a technican has in order to prevent the burden of legal liability is to be able to say he/she was following ONLY the manufacturer's recommended procedures during airbag service.

Now I'll jump off my soap-box and get back to this particular case. I think Ken probably has come to the conclusion that he simply cannot diagnose and repair this airbag system without a suitable scan tool. The DTCs simply cannot be cleared from these modules by simply resetting B+ for good reason. In many accidents the battery connection is comprimised, and while there is energy reserve capacitors built into the system to still insure deployment and event data recording, it would be important to the reconstructist to be able to extract any DTCs that existed at the time of the accident. This could not happen if the DTCs were stored in any sort of volatile RAM. So assuming Ken has replaced the airags as well as any of the arming/discriminating sensors that have triggered or are in the "area of accident damage" (in accordance to the manufacturer's recommended procedures), then ON THIS SYSTEM he will be able to clear the DTCs, clear the warning light, and put the system back into a functional state.On newer systems (1996+) the latched DTCs would NOT be able to be cleared and the SDM would need to be replaced.

HTH
WOT
  ----- Original Message ----- 
  From: Ben & Cecilia Pena 
  To: diy_efi at diy-efi.org 
  Sent: Wednesday, April 20, 2005 10:39 AM
  Subject: [Diy_efi] RE: Reset ECM after replacing airbag? (Ken)


  Ken,

  Some background first, I worked for an airbag manufacturer as a Test Technician and Test lab supervisor. We did all of the Testing of the airbag inflators and the airbag modules. I currently work for a company that supplies airbag initiators and seatbelt pretensioners to companies that supply to the auto manufacturers. I am the test lab supervisor here as well.

  The reason I mention all of this is that if the diagnostic system for the Inflatable restraints (airbags) cannot measure the bridgewire resistance of the initiator in the airbag and or measure / verify any of the sensors within the system you get the light on the dash. Did you replace the airbag yourself? If so, where did it come from? I would venture to say that the airbag and or one of the sensors is bad since you said that all of the wiring is and connections are good. If you replaced the airbag then you know how it is mounted in the steering wheel and where the connector is in the steering column. You can verify the Initator bridgewire resistance by disconecting the wiring and measuring with an ohm meter across the two leads or pins in the connector. It should be either ~ 1 ohms or ~ 2 ohms of resistance if you get any thing other than these values the airbag is no good. The reason for the two different resistance values is because there are two different bridgewire resistance requirements for different manufacturers. If your airbag measures good, then there is something within the inflatable restraint system that is bad. Hope this helps.

  -Ben   

  >Message: 6 
  >Date: Tue, 19 Apr 2005 13:45:00 -0500 
  >From: "Ken" <kenvc at msn.com> 
  >Subject: RE: [Diy_efi] Reset ECM after replacing airbag? 
  >To: "'jb'" <jonnbell at gmail.com>, <diy_efi at diy-efi.org> 
  >Message-ID: <BAY3-DAV109FF4729E587FFA067000B02A0 at phx.gbl> 
  >Content-Type: text/plain; charset="us-ascii" 
  > 
  > 
  >JB, 
  > 
  >I've tried all of the suggestions sent to me so far, but the INFL REST light 
  >is still there. 
  > 
  >All items associated with the airbag deployment have been replaced and are 
  >connected properly. Disconnecting the positive battery terminal and touching 
  >it to the negative terminal, with and without the ignition turned on, 
  >pressing the brakes to discharge all remaining voltage, etc, etc, but 
  >nothing is getting rid of it.  The only thing I have not tried is a scan 
  >tool and I have not seen one for a 93 Vette that says it can reset the ECU 
  >to get rid of this type of code. 
  > 
  >If you or anyone else has a connection to a body shop or dealer that knows 
  >how to reset the ECU to get rid of the INFL REST Light on this 93 Vette, I 
  >would very much appreciate it. 
  > 
  >Thanks, 
  > 
  >Ken 
  > 
  >-----Original Message----- 
  >From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On 
  >Behalf Of jb 
  >Sent: Wednesday, April 13, 2005 8:48 AM 
  >To: diy_efi at diy-efi.org 
  >Subject: Re: [Diy_efi] Reset ECM after replacing airbag? 
  > 
  >i would tend to agree with the need for a scan tool to reset the ecu. 
  >however, something else you might not have thought of is that often the 
  >sensors that sense the impact need to be replaced as well.  they are usually 
  >on the core support somewhere.  i work at a body shop that does a lot of 
  >collision, so if that doesnt fix your problem let me know and i can find a 
  >definite answer from the bossman. 
  > 
  > > 
  > > From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] 
  > > On Behalf Of Ken 
  > >  Sent: Tuesday, April 12, 2005 9:43 PM 
  > >  To: diy_efi at diy-efi.org 
  > >  Subject: [Diy_efi] Reset ECM after replacing airbag? 
  > > 
  > > 
  > > 
  > > I recently restored and completely rebuilt my 93 Vette including a 
  > > custom engine.  I ended up doing the ECM tuning myself after giving up 
  > > on Ed Wright to get it right.  After that I got the car repainted and 
  > > actually got to drive it for about a month in pristine condition 
  > > before a farmer in a pickup took the front end off the car. 
  > > 
  > > To make a long story short, the airbag deployed during the collision. 
  > > I have since repaired the car and replaced the airbag and coil with a new 
  >one. 
  > >  I disconnected the power to the ECM hoping that would get rid of the 
  > > annoying INFL REST light on the information display but that did not work. 
  > > When you first start the car it blinks a few times and then stops 
  > > blinking and just stays on all the time. 
  > > 
  > > Does anyone know how to get rid of the pesky INFL REST light now that 
  > > the airbag has been replaced. other than by removing the bulb? 
  > > 
  > > 
  > > 
  > > Thanks! 
  > > 
  > > Ken 
  > > 
  > > 
  > > _______________________________________________ 
  > > Diy_efi mailing list 
  > > Diy_efi at diy-efi.org 
  > > http://lists.diy-efi.org/mailman/listinfo/diy_efi 
  > > 
  > > 
  > > 
  > 
  > 
  >------------------------------ 
  > 
  >Message: 7 
  >Date: Tue, 19 Apr 2005 15:29:39 -0400 
  >From: Bill Shaw <b.shaw at comcast.net> 
  >Subject: Re: [Diy_efi] fast-ish 6 channel  data logger 
  >To: <diy_efi at diy-efi.org> 
  >Message-ID: <BE8AD463.5BB4%b.shaw at comcast.net> 
  >Content-Type: text/plain; charset="US-ASCII" 
  > 
  >If you can work with 4 channels Dataq has a PC-based system for $25, but 
  >needs a PC to collect the data. 
  > 
  >http://www.dataq.com/194.htm 
  > 
  >hth 
  > 
  >Bill 
  > 
  > > From: "Gianmarco Rizzo (BE/EAS)" <gianmarco.rizzo at ericsson.com> 
  > > 
  > > Hi all 
  > > 
  > > i am looking into a solution for a problem. 
  > > 
  > > i have a aftermarket EFI, and i would like to monitor exactly what happens 
  > > while cranking the engine, so as to see exactly when spark and fueling occur 
  > > in comparison with phase sensor pulses 
  > > 
  > > i have thought that perhaps a fast 6 channel data logger can help me there, 
  > > taking 2 injectors, 2 coils and 2 phase sensors data fast enough to 
  > > reconstruct the few seconds during cranking and see when different events 
  > > occur. 
  > > 
  > > so i wondered if anyone has info on how to build this or something available 
  > > on the market that wont cost more than the motorbike i am running the 
  > > injection on :-) 
  > > 
  > > saluti 
  > > 
  > > gianamrco 
  > > _______________________________________________ 
  > > Diy_efi mailing list 
  > > Diy_efi at diy-efi.org 
  > > http://lists.diy-efi.org/mailman/listinfo/diy_efi 
  > 
  > 
  > 
  >------------------------------ 
  > 
  >Message: 8 
  >Date: Tue, 19 Apr 2005 13:42:42 -0600 
  >From: "WopOnTour" <wopontour at hotmail.com> 
  >Subject: Re: [Diy_efi] Reset ECM after replacing airbag? 
  >To: <diy_efi at diy-efi.org> 
  >Message-ID: <BAY10-DAV9970A241A494D85B66149BA2A0 at phx.gbl> 
  >Content-Type: text/plain; format=flowed; charset="iso-8859-1"; 
  > reply-type=original 
  > 
  >Please refer to my previous post- scan tool clear ONLY! 
  >GM TECH2 (dealer) or a Vetronix MASTERTECH are the only scan tools that I am 
  >aware of that will clear the DTCs and get your light off (assuming no fault 
  >exisits) 
  >Good Luck 
  >WopOnTour 
  > 
  >----- Original Message ----- 
  >From: "Ken" <kenvc at msn.com> 
  >To: "'jb'" <jonnbell at gmail.com>; <diy_efi at diy-efi.org> 
  >Sent: Tuesday, April 19, 2005 12:45 PM 
  >Subject: RE: [Diy_efi] Reset ECM after replacing airbag? 
  > 
  > 
  > > 
  > > JB, 
  > > 
  > > I've tried all of the suggestions sent to me so far, but the INFL REST 
  > > light 
  > > is still there. 
  > > 
  > > All items associated with the airbag deployment have been replaced and are 
  > > connected properly. Disconnecting the positive battery terminal and 
  > > touching 
  > > it to the negative terminal, with and without the ignition turned on, 
  > > pressing the brakes to discharge all remaining voltage, etc, etc, but 
  > > nothing is getting rid of it.  The only thing I have not tried is a scan 
  > > tool and I have not seen one for a 93 Vette that says it can reset the ECU 
  > > to get rid of this type of code. 
  > > 
  > > If you or anyone else has a connection to a body shop or dealer that knows 
  > > how to reset the ECU to get rid of the INFL REST Light on this 93 Vette, I 
  > > would very much appreciate it. 
  > > 
  > > Thanks, 
  > > 
  > > Ken 
  > > 
  > > -----Original Message----- 
  > > From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] On 
  > > Behalf Of jb 
  > > Sent: Wednesday, April 13, 2005 8:48 AM 
  > > To: diy_efi at diy-efi.org 
  > > Subject: Re: [Diy_efi] Reset ECM after replacing airbag? 
  > > 
  > > i would tend to agree with the need for a scan tool to reset the ecu. 
  > > however, something else you might not have thought of is that often the 
  > > sensors that sense the impact need to be replaced as well.  they are 
  > > usually 
  > > on the core support somewhere.  i work at a body shop that does a lot of 
  > > collision, so if that doesnt fix your problem let me know and i can find a 
  > > definite answer from the bossman. 
  > > 
  > >> 
  > >> From: diy_efi-bounces at diy-efi.org [mailto:diy_efi-bounces at diy-efi.org] 
  > >> On Behalf Of Ken 
  > >>  Sent: Tuesday, April 12, 2005 9:43 PM 
  > >>  To: diy_efi at diy-efi.org 
  > >>  Subject: [Diy_efi] Reset ECM after replacing airbag? 
  > >> 
  > >> 
  > >> 
  > >> I recently restored and completely rebuilt my 93 Vette including a 
  > >> custom engine.  I ended up doing the ECM tuning myself after giving up 
  > >> on Ed Wright to get it right.  After that I got the car repainted and 
  > >> actually got to drive it for about a month in pristine condition 
  > >> before a farmer in a pickup took the front end off the car. 
  > >> 
  > >> To make a long story short, the airbag deployed during the collision. 
  > >> I have since repaired the car and replaced the airbag and coil with a new 
  > > one. 
  > >>  I disconnected the power to the ECM hoping that would get rid of the 
  > >> annoying INFL REST light on the information display but that did not 
  > >> work. 
  > >> When you first start the car it blinks a few times and then stops 
  > >> blinking and just stays on all the time. 
  > >> 
  > >> Does anyone know how to get rid of the pesky INFL REST light now that 
  > >> the airbag has been replaced. other than by removing the bulb? 
  > >> 
  > >> 
  > >> 
  > >> Thanks! 
  > >> 
  > >> Ken 
  > >> 
  > >> 
  > >> _______________________________________________ 
  > >> Diy_efi mailing list 
  > >> Diy_efi at diy-efi.org 
  > >> http://lists.diy-efi.org/mailman/listinfo/diy_efi 
  > >> 
  > >> 
  > >> 
  > > _______________________________________________ 
  > > Diy_efi mailing list 
  > > Diy_efi at diy-efi.org 
  > > http://lists.diy-efi.org/mailman/listinfo/diy_efi 
  > > 
  > 
  > 
  >------------------------------ 
  > 
  >_______________________________________________ 
  >Diy_efi mailing list 
  >Diy_efi at diy-efi.org 
  >http://lists.diy-efi.org/mailman/listinfo/diy_efi 
  > 
  > 
  >End of Diy_efi Digest, Vol 2, Issue 35 
  >************************************** 


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