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I have a 2009 CTS that was running perfectly and sat in a garage for approximately 4 months. My stepmom tried to start it using the spare key which had a dead battery in the remote. When she tried to turn it over the starter never turned and the key was stuck in ignition. I put a new battery in the remote and a new battery in the car. I was able to get the key out by pushing the manual release under the steering column. Now when I tried to start it again I noticed several guages not working. My diagnostic reader gave a no communication with BCM message. My question is do I need to replace BCM or is there a way to reset it?
My diagnostic reader gave a no communication with BCM message. My question is do I need to replace BCM or is there a way to reset it?
These aren't the only two options to proceed. Let'* troubleshoot a little bit:
I don't see any need to replace the BCM yet, and I'm not sure what you mean by resetting it . . . perhaps like resetting a wireless router at home that gets confused? If so, this kind of confusion doesn't really happen with BCMs.
Does this car have multiple wires leading to the battery terminals? If so, are they all connected and their connections clean, dry, and unpainted?
Next, I'd use a volt meter to check continuity of all the fuses.
These aren't the only two options to proceed. Let'* troubleshoot a little bit:
I don't see any need to replace the BCM yet, and I'm not sure what you mean by resetting it . . . perhaps like resetting a wireless router at home that gets confused? If so, this kind of confusion doesn't really happen with BCMs.
Does this car have multiple wires leading to the battery terminals? If so, are they all connected and their connections clean, dry, and unpainted?
Next, I'd use a volt meter to check continuity of all the fuses.
What engine does this car have?
Does it have a manual or automatic transmission?
How many miles on it?
I did check all the fuses with voltage meter and they all checked out ok. The car has a 3.6 v6 with an automatic transmission and has 130,000 miles on it and was well maintained. What I meant about resetting the BCM is that it seems to be stuck in like a anti theft mode (I read somewhere that the bcm can go into a anti theft mode where it won’t let the engine turn over) is this true? I have a lot of experience working on cars but the Cadillac is new to me. Any advice would greatly be appreciated. Thanks
I did check all the fuses with voltage meter and they all checked out ok.
So 12V on both sides of each fuse? . . . or did you do a continuity check on each one?
Originally Posted by Jdd
What I meant about resetting the BCM is that it seems to be stuck in like a anti theft mode (I read somewhere that the bcm can go into a anti theft mode where it won’t let the engine turn over) is this true?
If it is doing this, it should show a padlock in the gauge cluster. From your owner'* manual:
It may sound like insanity, but I'd try this: Disconnect the battery for five minutes, then reconnect and try again.
Last edited by CathedralCub; Feb 11, 2025 at 12:07 AM.
Reason: Added four words and a period and an "a"
No luck so far. I unplugged battery for 5 minutes and it does same thing. When I turn key to start the theft light is off. Key will not come out of ignition either unless I manually push lever inside column. I also noticed that my two remotes don’t work at all. No door lock unlock, no trunk open and no panic alarm. Any ideas ????
Originally Posted by CathedralCub
Hi Jdd, I'll post your reply in the public thread, and then I'll reply there as well. We do all of our technical stuff in public so we can use the combined brainpower of all the members and so everyone can make use of whatever we figure out in the future. Please check it out and use the thread to continue with troubleshooting this issue.
I did check all the fuses with voltage meter and they all checked out ok.
Originally Posted by CathedralCub
So 12V on both sides of each fuse? . . . or did you do a continuity check on each one?
. . . ?
Also, you checked all fuses in which fuse box(es)?
Originally Posted by Jdd
What I meant about resetting the BCM is that it seems to be stuck in like a anti theft mode (I read somewhere that the bcm can go into a anti theft mode where it won’t let the engine turn over) is this true?
Originally Posted by CathedralCub
If it is doing this, it should show a padlock in the gauge cluster.
Originally Posted by carfixer007
Also What is the theft light doing? Key on and when in start mode.
Originally Posted by Jdd
When I turn key to start the theft light is off.
Good to know, thanks! Based on this, I don't think we are worried about it being in anti-theft mode.
I'd like to know what voltages you see on both sides of each of the following fuses:
BCM 1:
BCM 2:
BCM 3:
BCM 4:
BCM 5:
BCM 6, BCM 7:
ECM:
ECM/TCM IGN:
Last edited by CathedralCub; Feb 11, 2025 at 12:08 AM.
Reason: Added picture
2009 Cadillac CTS won’t turn over.
