WS6HUMMER

iTrader: (19)

I wired my trans brake & Line lock together and used the "ign" terminal which just under the Gauges fuse. I had the line fused but after testing it out for a few seconds the Gauges fuse popped. I replaced the fuse & tested the "ign" circuit & it had power again, pulled the gauges fuse and it had no power again so I guess the "ign" circuit is fed off the gauges circuit. I started the car again and pulled it into my carport and figured I'd mess with it the next day. Well the next day I go to fire it up and it does nothing when I hit the key, everything comes on but the starter will not engage and I have the P1626 DTC. Well to make this story short, I found that by jumping the yellow & black wire of the starter relay to ground the car will turn over and start up for just a few seconds, the BCM supplies the yellow & black wire its ground BTW. I have HPT and I bet it would stay running if I deleted VATS but I really dont want to. So I guess my question really is that if I replace the BCM what else do I need to do? Do I need to have a new key/VATS pellet made to match that BCM? Will I have to reprogram my key fob?

Thanks

Hummer

wrencher

iTrader: (2)

You need to fix the theft deterrent system first.
Is the security light in the dash flashing or staying on?
No other fuses blown?

WS6HUMMER

iTrader: (19)

Never had an issue with the security before, the car wouldnt even turn over so I checked it for DTC's and got the 1626. These issues both came at the same time.

WS6HUMMER

iTrader: (19)

OK, Wrencher I think you may be right. I swapped out my BCM with 2 others, and still have all the same problems. I probed the 15A starter fuse in the underhood block and it gets voltage when I turn the key to the start position. All I know is that whatever my problem is, its causing something to tell the BCM its not OK to start and the BCM dosent send the ground signal needed to operate the starter relay.

wrencher

iTrader: (2)

Vehicle operation is disabled if incorrect key or starting procedure is used. Theft deterrent module enables crank circuit to starter and sends a signal to PCM if correct key is being used. If proper signal does not reach PCM fuel enable signal circuit, PCM will not pulse injectors on, disabling vehicle, even of crank circuit is by-passed. Signal should be 40-60 Hz.
DTC will set when PCM does receive the 40-60 Hz signal from the Body Control Module (BCM) and condition is present for less than one second.

This is the first 3 steps of the diagnostics for a P1626;
1) Perform On-Board Diagnostic (OBD) system check. See ON-BOARD DIAGNOSTIC (OBD) SYSTEM CHECK under SELF-DIAGNOSTIC SYSTEM in SELF-DIAGNOSTICS INTRODUCTION article. After performing OBD system check, go to next step.
2) Turn ignition on, with engine off. Using scan tool, select DTC option and SPECIFIC DTC option, then enter this DTC. If scan tool indicates that this DTC failed this ignition cycle, go to next step. If scan tool does not indicate that this DTC failed this ignition cycle, see DIAGNOSTIC AIDS.
3) If engine cranks, go to next step. If engine does not crank, diagnose theft deterrent system. See appropriate ANTI-THEFT SYSTEMS article in ACCESSORIES & EQUIPMENT.

Sounds like the BCM is not getting the right input from the theft deterrent module.
It wont crank because of the BCM & the PCM gets no fuel enable signal from the BCM.
So you have to fix the theft system first.

WS6HUMMER

iTrader: (19)

Thanks for the help, I ohmed the 2 white wires like you suggested and they have no continuity. I work at a salvage yard so I got a lock cylinder & key today (free) and now I just need to order some blank keys with my car resistance & have them cut for the new lock cylinder.

jay_lt4

iTrader: (4)

just find someone with hptuners or tunercats obd2 and have the vats turned off in your ecm, then just leave the starter enable relay jumped and anytime you crank the engine it will start without the bcm

i would turn the vats off no matter what,, we see so many cars get towed in because the wires break off at the ign cylinder,, nothing like being stranded because of something so stupid

WS6HUMMER

iTrader: (19)

Thanks for the suggestion, I still wanna keep the VATS though. Probably a bad idea & will leave me stranded, but I have HP tuners and a flat bed International wrecker.

Infantrymarine

iTrader: (3)

Hey there Hummer. Just wondering if you got your issue resolved. I have the same problem, except mine happened after a cam and valve spring swap. Only thing I can figure, is I must have yanked a wire loose when I was moving the wire loom to get to the back cylinder on the pass. side. Any thoughts? Am I thinking correctly? Wrencher chime in as well.

WS6HUMMER

iTrader: (19)

Yeah, Wrencher suggested to ohm the 2 white wires in an orange jacket that come out of the column (unplug them from the main harness first). Whatever the pellet resistance is should be what the wires read, mine= 0/OL. Its funny the way it happened, just like your car I had just rewired my trans brake & Line Lock, I just knew it was something I did but no it wasn't.

Patsy57

iTrader: (37)

When you say "Jump the Starter Relay" Where do I jump it to? Any pics?

WS6HUMMER

iTrader: (19)

Look for a light gauge yellow wire, leaving the BCM or you can jump it at the starter relay under the hood. This is a GROUND wire, jump it to ground. For the car to start you will have to turn off VATS in the tune for the engine to get fuel. If you ask me though its way easier to just ohm your key and put together some resistors from radio shack equaling the same impedance as your key. You wire 1 end of the resistor/resistors to one of the VATS wires & the other side to the other VATS wire.

If you bypass the security by jumping the yellow starter relay wire and turn off VATS in the tune it will run but you will have to look at the security light blinking on the dash all the time. With the resistor "mod" the light will go out, I did it both ways and would recommend using the resistors if you can.

1_bad94Camaro

iTrader: (15)

I know this is an old thread but i'm getting the same code on my Sierra. It starts then shuts off due to the fuel being cut off by the PCM. I've misplaced my original key so I'm using a cut key that I had made for a spare. The keys are not chipped or pilled. I can communicate to the PCM with my Snap on Solice but i'm not able to communicate with the BCM. Any tips or things to look for?

WS6HUMMER

iTrader: (19)

What year is the truck? I've had dealt with a few here @ work, if its a 00 there is something in the key the BCM is looking for. When that happens you have to do the relearn procedeure.

lt1pwr1

iTrader: (1)

I'm assuming you have the new style 99 Sierra? Those security systems are different. They use a Passlock system which probably isn't any better than the security systems in the past. You see alot of these with bad Passlock sensors. Does your Snap on scanner not read body codes?

WS6HUMMER

iTrader: (19)

Thats the system I'm thinking it has, we do a lot of engine installs where I work and have to do the relearn procedure if a truck has been sitting for a while with no battery.