1998 Buick La Sabre Passkey Bypass Diagram

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Passkey bypass

• Thread author tecktinkershop
• Start date Oct 12, 2017

• #1

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Buick Ownership

Buick

I have a 99 Buick LeSabre. The passkey module has given me quite a bit of trouble. First time it quit I "fixed it" by wiring a resistor in line the same resistance of the key. That worked for a while, until now. Drove home one evening, parked it, then got ready to head to work the next day, turned the key and nothing happened. I did my research online and then ordered the newrockies module to do away with the theft deterrent module. Got that wired in and the light on the box wouldn't come on. Did some testing and the box is getting no power. Double checked the wiring, checked the vats fuse, and still got no power. I jumped power to the box and got the car to start 1 time. Now it just crabs and won't start. My question is, how exactly does the theft module work? Could I just run wires to the fuel pump relay, and the ignition and starter through a set of toggle switches and make the car run? Or does the pcm absolutely have to have the signal from the module to work correctly? Any help would be appreciated. Thank you

• #2

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Buick Ownership

1997 Lesabre custom

I had a similar problem on my 97. The resistors I put in had lost contact. I had taped them in because I didn't have enough room to solder them in. I readjusted the resistors and it's been working fine since. That was may of 2016. My security light is still on all the time though. From what I researched it appeared that everything in the anti theft system was based on the resistance from the key. I could be wrong though.

• #3

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Buick Ownership

1996 Roadmaster Limited Collectors Edition 58k - 1996 PAU 2019 Regal GS

Double checked the wiring, checked the vats fuse, and still got no power.

Which fuse did you check? There are two fuses for the PassKey system, 1A & 2E, which is shared with the air bag system. 2-E is the most important.

Now it just crabs and won't start.

Do you mean it cranks, but will not start?

Could I just run wires to the fuel pump relay, and the ignition and starter through a set of toggle switches and make the car run? Or does the pcm absolutely have to have the signal from the module to work correctly?

It is my understanding that the NewRockies module totally eliminates the TDM/BCM portion of the system. The PCM controls the injector firing, so jumping the fuel pump would not provide the fuel to the cylinders.

Or does the pcm absolutely have to have the signal from the module to work correctly?

That is correct!

Antitheft Signal: Description and Operation

When the ignition is turned "ON", the PASS-key (registered trademark) decoder "reads" the key resistor pellet. If the proper resistance is recognized by the decoder module, it sends a PWM fuel enable signal to the PCM. The PCM looks for this signal during crank and allows fuel delivery by enabling the injectors when the signal is recognized. If the fuel enable signal is lost while the engine is running, the PCM will store code 58 and the vehicle will run normally. As long as code 58 is stored, the PCM will ignore any absence of the fuel enable signal and the car will start and run as long as the problem is isolated to the fuel enable circuit only.

Last edited: Oct 13, 2017

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