security light on?
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security light on?
This one is got me. 2000 coupe AT. Security light stays on while driving
"sometime", the key FOB will not work unless it is syncd. and then will only work for a few cycles, about 1 minute then will not work again untill re-syncd. After several cycles of the FOB, the car will not start untill the battery is disconnected fro approx. 30 minutes. If I do not mess with the FOB I don't have a starting problem. I suspect this is all connected but I am totally lost. I NEED HELP.
Bill
"sometime", the key FOB will not work unless it is syncd. and then will only work for a few cycles, about 1 minute then will not work again untill re-syncd. After several cycles of the FOB, the car will not start untill the battery is disconnected fro approx. 30 minutes. If I do not mess with the FOB I don't have a starting problem. I suspect this is all connected but I am totally lost. I NEED HELP.
Bill
Tech Contributor
Joined: Jan 2007
Posts: 19,246
Likes: 1,095
From: Dyer, IN
This one is got me. 2000 coupe AT. Security light stays on while driving
"sometime", the key FOB will not work unless it is syncd. and then will only work for a few cycles, about 1 minute then will not work again untill re-syncd. After several cycles of the FOB, the car will not start untill the battery is disconnected fro approx. 30 minutes. If I do not mess with the FOB I don't have a starting problem. I suspect this is all connected but I am totally lost. I NEED HELP.
Bill
"sometime", the key FOB will not work unless it is syncd. and then will only work for a few cycles, about 1 minute then will not work again untill re-syncd. After several cycles of the FOB, the car will not start untill the battery is disconnected fro approx. 30 minutes. If I do not mess with the FOB I don't have a starting problem. I suspect this is all connected but I am totally lost. I NEED HELP.
Bill
http://www.c5forum.com/ayc/dtcdic.php
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security light stays on
Ran the codes, all "H" except B2721 H & C. All cleared except this one. Started car , ran for 5 minutes. Ran codes again B 2721 H&C. Security light still on. Car sometimes starts, i.e, starter engages. if not disconnect battery for 30 minutes, even then sometimes will not start. key fob will not work unless syncd. After syncd will work for 1 or 2 cycles, then nothing, must be re-scynd. Light stays on. New Delco battery, fully charged. Please help! Thanks
Bill
Bill
Tech Contributor
Joined: Dec 1999
Posts: 32,910
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From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
B2721 H & C Is the PASS KEY DETECTION CIRCUIT DTC. Thats causing the security issues. The resistor chip in your key is either dirty, damaged or both. Do you have a spare key? If so try it and see if it resolves the security issue. If its not the key causing the issue, the sensor on the end of the ignition switch is not well.
If all else fails, you can bypass that circuit. Its not easy but with a little time and effort, that can be resolved.
You have other issues also. Lets get the B2721 H & C Is the PASS KEY DETECTION CIRCUIT DTC resolved first. Sometimes multiple issues mask symptoms of other issues.
BC
If all else fails, you can bypass that circuit. Its not easy but with a little time and effort, that can be resolved.
You have other issues also. Lets get the B2721 H & C Is the PASS KEY DETECTION CIRCUIT DTC resolved first. Sometimes multiple issues mask symptoms of other issues.
BC
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From: Van Buren Arkansas
Wounded Warrior Escort '11
The FOB sync issue is probably a 2nd problem, therefore not necessarily associated with the security issue. The FOB itself is probably starting to die. Bill is the expert with the security issues of course so follow his advice to the letter.
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No start, ran diagnostics, no codes except P1631 H &C, was able to clear, waited 1 hr. car started and drove normally for about 5 miles, security light off, HORRAY, problem fixed/ Next trip 2 hours later light came on after approx 5 minutes. Started & re started several times ok but light still on. Next morning, no start, ran diagnostics no codes except P 1631 H&C and B 2721 H cleared waited 10 minutes, no start. What now? I have only owned this car for 6 months, it was from Fla. excellent condition,62K
Thanks
Thanks
Last edited by william mikesell; Apr 5, 2010 at 10:01 AM. Reason: TYPO
Tech Contributor
Joined: Dec 2006
Posts: 10,962
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From: Van Buren Arkansas
Wounded Warrior Escort '11
P1631 Theft Deterrent System Password Incorrect
The PCM and BCM share a hidden password between them and if it doesn't match on both ends, the car will not start. Now since it does start and not start at times, suggests that the password isn't the issue, rather the communication of that password. The first thing that comes to mind is the serial data buss connector next to the BCM. Bill Curlee has some great pictures of that connector called a "star connector". There should be a shorting bar there on it which probably needs to be cleaned but this is all in the passenger footwell. There is a security relearn procedure for the password which you can do as well, but I'm thinking that won't solve this issue.
B2721 PASS-Key Detection Circuit
This is saying the chip in the key was not read correctly and it too will stop the car from starting. Either the chip's contacts are dirty or the chip contacts in the column are dirty or wearing out.
The PCM and BCM share a hidden password between them and if it doesn't match on both ends, the car will not start. Now since it does start and not start at times, suggests that the password isn't the issue, rather the communication of that password. The first thing that comes to mind is the serial data buss connector next to the BCM. Bill Curlee has some great pictures of that connector called a "star connector". There should be a shorting bar there on it which probably needs to be cleaned but this is all in the passenger footwell. There is a security relearn procedure for the password which you can do as well, but I'm thinking that won't solve this issue.
B2721 PASS-Key Detection Circuit
This is saying the chip in the key was not read correctly and it too will stop the car from starting. Either the chip's contacts are dirty or the chip contacts in the column are dirty or wearing out.
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security light on, no start
The latest in this nightmare. Started normally this AM, but light on. Drove about 10 miles, no problem, light still on. Shut down tried to re start, nothing. Ran the codes: B 2583H, B2721HC, U 1096H, U1064H & U1016H, ( what are these U codes?) Please, is there any kind of fix for this nightmare? Thanks for your help.
Respectfully,
Bill
Respectfully,
Bill
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Safety Car
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From: Boise ID
As suggested, it sounds like an intermitted problem with the pass key circuit. This would explain why sometimes the car does not turn over and other times it does start but security light is on.
I have not read if you followed Bill’s suggestion of trying a different key, or at least cleaning the pellet of the key you have.
From the manual:
If the PASS-Key® system detects an open or short to ground when the ignition switch is in the RUN position, the BCM will default to fail enable mode. Fail enable occurs when the proper key resistance is sensed before the open short to ground occurs. Fail enable will illuminate the security indicator lamp and allow the operator to stop and start the vehicle until the problem is corrected.
I have not read if you followed Bill’s suggestion of trying a different key, or at least cleaning the pellet of the key you have.
From the manual:
If the PASS-Key® system detects an open or short to ground when the ignition switch is in the RUN position, the BCM will default to fail enable mode. Fail enable occurs when the proper key resistance is sensed before the open short to ground occurs. Fail enable will illuminate the security indicator lamp and allow the operator to stop and start the vehicle until the problem is corrected.
Tech Contributor
Joined: Jan 2007
Posts: 19,246
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From: Dyer, IN
The latest in this nightmare. Started normally this AM, but light on. Drove about 10 miles, no problem, light still on. Shut down tried to re start, nothing. Ran the codes: B 2583H, B2721HC, U 1096H, U1064H & U1016H, ( what are these U codes?) Please, is there any kind of fix for this nightmare? Thanks for your help.
Respectfully,
Bill
Respectfully,
Bill
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
U Series DTC indicate that the MODULE it's related to, shut down for what ever reason. Most common cause is a LOW or WEAK battery.
Believe it or not, my C6 started doing the something. IPC started to freak out also. The battery is 4 1/2 years old. Time for a new one.
When a battery is discharged or aged, when it supplies a large current draw (like when you first engage the starter) (300 amps) battery voltage is inversely proportional and goes LOW. If it doesn't have enough voltage potential the voltage output can drop as low as 8 -9 VDC or less and when it does, modules shut down until the voltage comes back in range. Each module has a 9-15 VDC operating range. If you exceed either, they don't like it.
Once the starter gets the engine spinning it draws less current and the B+ voltage goes back into spec. Whats left is the History U series DTCs
When your car is dead cold, measure battery voltage directly at the terminals and have someone crank your car. When they crank your engine see how LOW the battery voltage drops to.
BC
Believe it or not, my C6 started doing the something. IPC started to freak out also. The battery is 4 1/2 years old. Time for a new one.
When a battery is discharged or aged, when it supplies a large current draw (like when you first engage the starter) (300 amps) battery voltage is inversely proportional and goes LOW. If it doesn't have enough voltage potential the voltage output can drop as low as 8 -9 VDC or less and when it does, modules shut down until the voltage comes back in range. Each module has a 9-15 VDC operating range. If you exceed either, they don't like it.
Once the starter gets the engine spinning it draws less current and the B+ voltage goes back into spec. Whats left is the History U series DTCs
When your car is dead cold, measure battery voltage directly at the terminals and have someone crank your car. When they crank your engine see how LOW the battery voltage drops to.
BC
Last edited by Bill Curlee; Apr 7, 2010 at 07:21 PM.
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Removed the circuit panel from the "silver box" in the p.footwell, still do not know what it is called, and found alot of corrosion on both sides. Cleaned with electronic cleaner spray, radio shack, and WOW light off, testdrove perfect, no codes, several starts, light is OFF, problem resolved! Hooray. Special thanks to Lucky131969, dgrant3830 and especially, Bill Curlee. Now I am working on the key fob problem, but at least I can drive the car and not worry about it starting, again thanks to all.
Sincerely,
Bill
Sincerely,
Bill
