Security light

2004 BUICK RENDEZVOUS
146,000 MILES • 3.6L • 6 CYL • 4WD • AUTOMATIC
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DOWDY1291
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Okay, see if someone can help me out. I see myself as a pretty good mechanic but I'm at my wits end.
So let me tell the whole story from the beginning, somewhere in June 2019 the security came on and car wouldn't start so I tried the key reset over and over and the battery finally died, so I decided I'm going to get a new battery, so I get a new battery and put it in and it started with no security light and ran for months, well back in late September 2019 the security light came back on, so I have the battery tested and it tested good so I didn't know what the problem was, I checked fuses and left the cables off hoping to reset but no avail, so I decided to buy another battery because computerized stuff is not my strong suit, so I buy another battery and security turns of immediately and works good for a few weeks, and it comes back on and car wouldn't start it was sitting at a gas station, after a few days it started back up and I drove it home with the security light on, it no longer says Buick it now says Delphi on the screen. it'll still crank and start now but none of the gauges work besides the speedometer. Can someone shed some light on this for me?
Nov 24, 2019 at 4:50 PM
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ASEMASTER6371
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Good evening,

This sounds like an issue with the body control module. I had one of these and had similar issues and it was the body control module.

Do you have a scan tool that can read the data and codes for the body control module?

Roy

REMOVAL PROCEDURE

IMPORTANT: You must perform the new body control module (BCM) setup when replacing the BCM. Refer to Body Control Module (BCM) Programming/RPO Configuration.

1. Disconnect the negative battery cable.
2. Remove the console accessory wiring junction block.


imageOpen In New TabZoom/Print

3. Rotate the BCM retaining lever (1) to release the BCM from the console accessory wiring junction block.
4. Remove the BCM (2) from the console accessory wiring junction block.
Nov 24, 2019 at 5:24 PM
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DOWDY1291
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So I tried the key reset about 4 days ago on this car and the battery died. so I decided to just let it drain it and put the new battery back in because I changed it out for the battery I bought back in June or so. I put the new battery in and turned the car on and security was still on, so I turned it on and off, by that I mean I started it and shut off 3 times and started it again and the security was off for a hour or so and then I let it idle and the security comes back on. seems like every time I let it idle the security comes back on. Still think this is a BCM problem?
Nov 25, 2019 at 10:33 AM
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ASEMASTER6371
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You would be able to tell if you had a scan tool that can read codes for the BCM.

Do you have a scan tool?

Roy
Nov 25, 2019 at 10:36 AM
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DOWDY1291
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I had the car scanned at a mechanic shop and he pulled the codes which was all security related. I didn't write the codes down like I should have. But he looked it up and showed me a list of what it could be by other mechanics and said 38 times it was the PCM and 22 times it was the BCM 13 times it was ignition and 6 times alternator but I didn't know anymore than I started. I don't have my own tech2 scanner yet but I am going to get one. Taking the car to the dealer tomorrow to get it diagnosed. Will post what they find out.
Nov 25, 2019 at 10:52 AM
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ASEMASTER6371
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Okay, you took it to a mechanic shop and they could not diagnose it? Shame on them.

I wish you could give me the codes.

Roy
Nov 25, 2019 at 10:55 AM
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DOWDY1291
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Update: Got home and check the voltage on a few things wanted to make sure the alternator but the car wouldn't start, it was no crank no start. that has happened a lot in security mode. I already have the plastic cover off the bottom of the column and started wiggling around on ignition switch and the car started up, but security was still on. so I turned it off and it was back to no crank no start, every time I wiggled it, it decided to start and every other time the security was off. Had to run to the bank and go do some shopping for Thanksgiving but decided something to do with ignition switch, going check the wires later, maybe buy a new switch. Will keep everyone posted on the task at hand.
Nov 25, 2019 at 11:36 AM
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ASEMASTER6371
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Sounds good.

Roy
Nov 25, 2019 at 11:38 AM