Dr Curlee i speak for everyone here: thank you so much!
to answer:
- I read codes from the DIC
- security light does not come on or flash (aside from when i first turn the key on)
- recently i have NOT tried disconnect/reconnect battery will do in 10 mins
- will also check HVAC and BCM as you advise
- and yes when i ground the yellow/black the car all is perfect

oh and they do make a keg of better thank wine- Frambois LAMBIC- they sell it in bottles with corks but recently the put it in kegs- scottsdale fashion square has it on tap
post in a little after i do as you told me to do thx george

 

battery is disconnected will reconnect in 5- i do have continuity from the TDR relay yellow/black to the BCM connector; i removed the BCM/ opened it and it looks like brandy new- no signs of water problem or clogged HVAC at all- i dont suspect the bcm has its own grounding issues as that would cause alot of other problems with codes- is there a way to reset the BCM? i ll be back after reconnect battery with more info
anyone want a 98C5 convertible in near perfect shape- oh, yea it doesnt crank

 

oh- i did notice relay 42 underthood is hotter than all the other things in the fuse box are underhood; AND, it is probably normal but the # 37 microrelay underdash clicks when i turn the key to crank position- ifigured i would change this just because but just trying to give more info- i also noticed my sterring wheel does NOT lock (hope that doesnt complicate things)

 

disconnected batter/reconnected with no change
i put the battery on charge just to rule it out- it is about 1 yr old but i guess one never knows

 

Is the wire making the circuit to the BCM? Read it out at the BCM connector. yes

is the BCM functioning correctly???
i dont know- i do know i dont get any codes- is there a way to tell if the BCM is working correctly or incorrectly? - i'd even send it somewhere or go to dealer to find this out (desperate times...)

 

finally a code: persistant P 1626 the darn P1626 Theft Deterrent System Fuel Enable Circuit !!! from what i can tell the actual module on the firewall took a dump- anyone know where to get one cheap or go with the baber electronix bypass- what would you do?
george

 

 

Replacing the TDR is just plug and play, but some will bypass it also. Referring to this schematic (1995), you can unplug the relay and join the yellow and purple wires together. This completely bypasses the relay.

You can also keep the relay (if it is working), but bypass the need for the TDM to operate it. Referring to the schematic, the yellow/black wire from the TDM to the TDR would need to be permanently grounded toward the TDR. Doing this only, will not affect the neutral safety or clutch switch operation. The relay will only operate when the switch is in the START position as that is the only time it would get 12v power.

 

Well my car is officially not starting anymore and now the steering wheel is locked. My security light is on and it does NOT blink. Will this resistor thing work at all and able to start my car or no? If anyone can help please let me know asap. Thanks.

 

Alright i tried everything. I am having codes B2723 and P1631. Im going to try the resistor bypass and if that works then i know its the ignition cylinder that is bad right?

Update: I did the resistor bypass and started right up. Guess my ignition cylinder is out.

 

just wondering: the two wires that it seems everyone accesses to bypass the VATS via removing the key itself from the circuit and adding a resistor = to the key resistance values is AT the steering column itself/at the lock cylinder- here is my question (after replacing the key and lock cylinder on my 98 C5...and switch too)- since the small black wires which connect to the lock cylinder ultimately terminate at the BCM - WHY dont we just connect the resistor between the two wires AT the much easier to access BCM ruling out any chance that somewhere from the cylinder/steering column these is a loss of continuity which will negate the bypass at that location?
anyway- no one locally in insane Tucson will flash out the VATS from my PCM but found someone in San Antonio for 75...OR will use an Idatalink immobilizer- either way it appear to be a 100 sort of 'fix'-
again i have no codes just have no ground at yellow to black at TDR and if i bypass this car start for about 1 second and then i lose my fuel

 

VATS is NOT in the PCM and can NOT be flashed out. Its in the BCM and its an integral part of the security system. Unless the correct resistance is seen in the VATS wires, the car isn't going to work.

The GM Tech 2 is the interface required to interface and update the BCM. You can change RPO related stuff in the BCM and do some PCM specific functions with it.

It will be interesting to see what this guy can do with an Idatalink immobilizer

BC

 

See no reason why the resistor couldn't be done at the BCM, different location same results ???

However lots of people are nervous when it comes to cutting wires at the BCM. The reason for the resistor there might be difficult for the next owner/buyer to figure out it's purpose.

 

Nelson performance in san antonio told me they can 'deactivate/inactivate' the entirety of the antitheft/VATS/etc. by sending them my PCM for 75 which i figured i can live with even if it doesnt do as i hope it will- i am sending it tomorrow
my understanding of the idatalink (or equivalent such as the Audiovax data immobilizer bypasses) is that if you want to install a remote starter in my 98 C5 there MUST be an inactivation of the antitheft system which INCLUDED a bypass of the key, the TDR AND the fuel enable/disable at least that is what i was advised from lesscoelectronics back in NY who told me he understood exactly what i was trying to do and that in addition to the FlashLogic FLTB2 GM Passkey Databus Bypass Module i would also need a relay which utilized the pink wire at my ignition and several other wires (which he would send me the wiring diagram which would accomplish this) during this conversation i advised in the install manual of the FlashLogic FLTB2 GM Passkey Databus Bypass Module it appeared that only the key resistor was bypassed- he replied the FlashLogic FLTB2 GM Passkey Databus Bypass Module with this added relay wired would do as i wanted- since i didnt purchase this from him i am sorry i do not have all the detail but it seems most- tonight i am going to reinspect EVERY fuse and unless i find something blown i will send my pcm to texas- i was also advised this is a completely reversible change that will generate no codes so i figure i can throw a 100 or so at the car even if just for diagnostic purposes- the southern az corvette club steered me to a local place that if i fail i will probably bring to them- 90 to diagnose and then go from there- i felt comfortable with them as they freely had me speak with several of the mechanics and owner- more to follow oh ps- it is my undertanding all of these data immobilizers do the same thing but NONE of them appear to have any interaction with the fuel enable circuit - boy do i wish, for diagnostic purposes i knew how to apply the 5 Volts (i believe) to where to keep the fuel circuit and consequently fuel going...i ll at some point be an expert on stealing these things lol
thanks again!!!! more to follow

 

ICUALL - regarding:
See no reason why the resistor couldn't be done at the BCM, different location same results ???

the reason i have not tried this for Diagnostic purposes is there are several purple/wht and wht/blk wires at my BCM and also at different places on my BCM- and i cant read where the B2 or A3 areas are... AND over 3 connectors to my BCM... and those other two (sorry) white i guess busses which connect via a clip to the body which are next to the BCM but are definitely connected via wires to the BCM my 71 GS is looking real good about now!

 

http://www.c5help.com/bcm_connections.htm

 

man i owe everyone here a case of beer- excep for Bill- a vat o vino! thx ill check it out now

 

Did the bypass this past weekend...everything is working great!! No more embarrassing "NO STARTS"

Thank you all for the detail and awesome pics!!!

 

Evaporator drain stopped up and caused a little moisture on the BCM. Cleared all that up then the car would not start. No problem just consult the Forum. Found out where the evaporator drain was, and how to let the car relearn the VATs code of the keys!!! I don't know how many time the Forum has saved my bacon. Thanks guys.

 

It has been a LONG time but I am adding a comment- and thank you all so much for understanding my car and saving me ton of $ so here is an idea???? I have read that for example I bought a USED BCM there would be a 1 in 15 chance (theoretically) as there are 15 different key resistor pellets and the pellet value MUST match the BCM (when the BCM was forst put in the car it reads this resistance value and then stores it PERMANENTLY in the BCM... Please advise on my idea as crazy as it may sound- would there be any problem with putting a used BCM in my car and just have (please dont laugh at this idea lol) but seriously- if I had all 15 different keys with all 15 different resistance values- there should be no problem doing this, correct???? last year for like 5 months i could not locate a single BCM, fortunately got car running but i still need a BCM- so any thoughts on this???? thx!!! George