error code p1631

[biglionholland]

hello,

i need help with this error
engine wil not start after this probleem



Mart

from holland

[Quig653]

See if this link helps. It appears to be a "passlock" security code and can be reset.

http://www.obd-codes.com/forums/viewtopic.php?f=2&t=3818

Good Luck,
Quig

[More Power]

P1631 - Theft Deterrent System-Password Incorrect

This is likely either an ignition keylock assembly or a BCM (Body Control Module) problem.

There is a Hall-Effect sensor located in the ignition lock assembly that outputs a resistor code when the ignition lock is rotated normally. This code is then sent to the BCM, where it is compared to the code it has stored for that vehicle. If the code is valid, a "fuel continue" message is then sent to the vehicle's ECM.

If the code is not valid, the engine will crank and may run for a second or two, then die. As far as I know, this fuel continue message is only looked at during the start cycle.

I had to deal with this when my Duramax conversion came together in early 2004. In my case, I performed the "Password Learn" procedure as outlined in the service manual (about 35 minutes). A dealer tech with a Tech II Scan Tool can perform the same process in much less time. There are ways to work around this problem when using a different steering columnn and ignition lock assembly that doesn't have Passlock capability. ;)

Jim