[bharat9569567]

Well, the 12V disconnect fixes problems where the car just needs a good reset, but if you have more of a permanent fault - it unfortunately won't help there.

Regarding charging the 12V battery, this is probably best covered below. I believe I know what you did wrong. With the battery negative disconnected, you cannot use the GRND jump start terminal. You have to connect the battery charger negative lead direct to the battery negative post, and same for the positive.

It is certainly worth a try to charge up the 12V battery. I'm not sure which faults you have, but perhaps charging it up will get it happy enough to get into gear and drive.

https://www.cadillacforums.com/threads/12v-battery-issue.1134949/page-3#post-18184295

Thank you so much for the reply!

Quick update,
Instead of fiddling around with it, I just got it towed earlier today for service. At this point, the car had completely drained, doors wont open and all of that. The person who came to tow the car told me they boosted the 12V battery (I was at work at the time), and the car once turned on was able to go into Reverse to back out the garage, and then into Neutral. So I am assuming the errors were fixed, since it could shift now. Originally it was throwing a bunch of errors in my face and giving me "conditions not met for shift".

I asked him which terminals he used over the phone and he mentioned he used the GRND cover terminal.. so I guess that is the correct one?

I informed him that I tried to boost it yesterday and it didn't work for me. He said he also couldn't get it to boost at first, but then he amped up his booster and it worked. I asked for the Amps on his booster, and he said 2000. I think mine was < 100, so that may explain why mine didn't work.

One question for you..
Any idea why resetting (disconnecting & reconnecting) the 12V battery terminal as outlined in your post doesn't fix the issues in the car, but letting the 12v battery completely drain out and then boosting it allows the car to shift ? (cant confirm if it got rid of all the errors, I have the tow drivers personal # so I will call him tomorrow to confirm if he saw errors after he boosted it)

Another idea could also be that once the car phantom drains the 12v past a certain point, then the car can still turn on but all these errors start popping up. Maybe it just needs a boost to get past a certain point? I'm not too sure.


Anyway, its a complete bummer that this has happened for the fourth time. I really thought they had fixed it permanently the last time. I'm in Canada so I think the codes for the module updates are different.

Have a second question for you.. do you think it can be a faulty 12V , and not an issue of phantom drain?

I have noticed this same issue keeps happening every 3-4 weeks.

Thanks so much for the help!
I love this car, I'm really hoping all of this gets solved and its more software related than hardware related.

 

[hightech-guy]

Thank you so much for the reply!

Quick update,
Instead of fiddling around with it, I just got it towed earlier today for service. At this point, the car had completely drained, doors wont open and all of that. The person who came to tow the car told me they boosted the 12V battery (I was at work at the time), and the car once turned on was able to go into Reverse to back out the garage, and then into Neutral. So I am assuming the errors were fixed, since it could shift now. Originally it was throwing a bunch of errors in my face and giving me "conditions not met for shift".

I asked him which terminals he used over the phone and he mentioned he used the GRND cover terminal.. so I guess that is the correct one?

I informed him that I tried to boost it yesterday and it didn't work for me. He said he also couldn't get it to boost at first, but then he amped up his booster and it worked. I asked for the Amps on his booster, and he said 2000. I think mine was < 100, so that may explain why mine didn't work.

One question for you..
Any idea why resetting (disconnecting & reconnecting) the 12V battery terminal as outlined in your post doesn't fix the issues in the car, but letting the 12v battery completely drain out and then boosting it allows the car to shift ? (cant confirm if it got rid of all the errors, I have the tow drivers personal # so I will call him tomorrow to confirm if he saw errors after he boosted it)

Another idea could also be that once the car phantom drains the 12v past a certain point, then the car can still turn on but all these errors start popping up. Maybe it just needs a boost to get past a certain point? I'm not too sure.


Anyway, its a complete bummer that this has happened for the fourth time. I really thought they had fixed it permanently the last time. I'm in Canada so I think the codes for the module updates are different.

Have a second question for you.. do you think it can be a faulty 12V , and not an issue of phantom drain?

I have noticed this same issue keeps happening every 3-4 weeks.

Thanks so much for the help!
I love this car, I'm really hoping all of this gets solved and its more software related than hardware related.

What you describe is identical symptoms to the 12V system faults from last summer, and then again later with the early 2024's. The 12V battery will be either partially drained and you have some functionality or faults, or dead enough that you can't get in the car. And you can use a jump pack to get the car powered up enough to get it into neutral, but when you remove it the car is dead again.

The reason the tow driver used the GRND terminal is because he didn't disconnect the 12V battery. However, assuming the fault behaves the same as before, to resolve this you need to have the battery disconnected, charge the battery directly, and reconnect. If you try and charge the battery with a the negative lead disconnected and use the GRND post in the car, there is no circuit to charge the battery. As mentioned, you do need to charge the battery when disconnected from the car, as the load of the car will not allow the battery to charge from a low power charger or jump pack given the bad state the car's modules are in.

Good luck with getting things fixed, and please keep us posted on how the repair goes.

 

[bharat9569567]

What you describe is identical symptoms to the 12V system faults from last summer, and then again later with the early 2024's. The 12V battery will be either partially drained and you have some functionality or faults, or dead enough that you can't get in the car. And you can use a jump pack to get the car powered up enough to get it into neutral, but when you remove it the car is dead again.

The reason the tow driver used the GRND terminal is because he didn't disconnect the 12V battery. However, assuming the fault behaves the same as before, to resolve this you need to have the battery disconnected, charge the battery directly, and reconnect. If you try and charge the battery with a the negative lead disconnected and use the GRND post in the car, there is no circuit to charge the battery. As mentioned, you do need to charge the battery when disconnected from the car, as the load of the car will not allow the battery to charge from a low power charger or jump pack given the bad state the car's modules are in.

Good luck with getting things fixed, and please keep us posted on how the repair goes.

Good morning,
I see makes sense. I guess I'll have to wait again to run into this issue. I will see if I can find the service report from last time to see what they they updated and compare it with the service from this time (comparing the two codes, I forget how they start, something like PTB6065)

If I get the 12V battery replaced aftermarket from a third party, does this void my warranty?

 

[hightech-guy]

Good morning,
I see makes sense. I guess I'll have to wait again to run into this issue. I will see if I can find the service report from last time to see what they they updated and compare it with the service from this time (comparing the two codes, I forget how they start, something like PTB6065)

If I get the 12V battery replaced aftermarket from a third party, does this void my warranty?

If they are following normal procedure with these faults, they should test the 12V battery on the special tester they have. It outputs a report, and that is needed to provide to TAC in order to authorize a replacement 12V battery. From what you describe, it sounds more like a car module parasitic load issue (and likely software related) than a battery problem. When this happened last year, 12V batteries were being replaced and that wasn't solving the issue - and the batteries weren't bad (hence the testing procedure now dictated by the related TSB's).

You mentioned this is now the 4th time this has happened to you? If that is the case, they may change the 12V battery proactively as well. But it sounds like they are missing something when applying the car software updates, or you have some unique situation going on.

No reason you couldn't purchase a new 12V battery and change yourself, but I would expect that will cause trouble should this problem repeat. It will likely be blamed, regardless if true.

 

[Ttrm007]

Steps to do a 'hard' reset of the car's electronics by a 12V battery disconnect and reconnect. Do this in an attempt to resolve issues like modules offline or other functions not working - when a trip to the dealer is not possible or convenient. This is my own approach by performing and documenting the process. Hope this is helpful, and feel free point out any issues or improvements. Steps, photos, and tips below.

Power down and disconnect procedure:

1. Power off vehicle
2. Open drivers door, and leave door open
3. Wait over 5 minutes for car to go to sleep
   1. Can do next steps during this time, just don't disconnect cable until time has lapsed
4. Open hood
   1. Pull hood release (lower left instrument panel) two times
   2. Lift open hood (has hydraulic struts to hold open by itself)
5. Remove central plastic cover
   1. Pull cover up at handhold near windshield (or lift up at front lip) - un-popping 6 plastic clips
6. Remove metal bracket over top of negative terminal
   1. Use a fixed 10mm wrench or socket with extension to remove 2 nuts (one nut is partially under the plastic frame - may be accessed better with a fixed wrench)
   2. Remove bracket
7. Loosen battery negative lead with 10mm socket
8. Pull up on negative battery lead to disengage from battery post
   1. After battery lead removal, insert something non-conductive (cloth or glove) between the battery post and the disconnected lead so it remains disconnected for a period of time
9. Test that vehicle has no power
   1. Try to open rear door, and check interior lights. Confirm no operation / no power.
   2. If power is still present, let vehicle sit for several minutes more. This just means that vehicle wasn't asleep when 12V battery cable was disconnected, and power is still being supplied to the 12V systems by the high voltage battery and DC-DC converter. After a period of time, recheck power until confirmed that vehicle has no power.

Reconnect and power up procedure:

1. Reconnect negative battery cable and tighten nut.
   1. A small spark will sometimes occur and is normal
2. Replace bracket and two nuts above negative terminal portion of battery
3. Replace central plastic under hood cover
   1. Align and apply pressure at each of the 6 snap points until the snaps click back into place.
4. Close hood
   1. Need to lower to about 1 foot, than drop / force down rapidly
5. Enter vehicle and power on
6. All functions should work, but a few things may need to be reset as below...
   1. Tire pressure will be blank until driving about 1/2 mile
   2. Auto-high beams headlight setting should be checked - 'on' setting is not retained
   3. Rear-seat reminder feature should be checked - 'off' setting is not retained
   4. Instrument cluster may prompt you to open and close all windows. It will step you through the process, opening then closing each window. This is to re-calibrate the auto-reverse system. Express-up will not function until the window has been opened then closed.
   5. Depending of software version, there may be other somewhat less obvious settings that aren't maintained. Work through the menus to double check.

Tips:

• You can't reliably disconnect the negative battery lead without removing the metal bracket that is over the top of it. The battery lead can't be raised up sufficiently to clear the battery terminal and not contact the bracket.
• If you are attempting to use a socket for both the bracket nuts and battery terminals, you can't access the inner-most nut off the bracket because the interfering plastic support frame that is partially in the way. To allow a socket to be used, remove the T30 torx screw from the top of the plastic frame. With the screw removed, the plastic support frame can be pulled up and out of the way a bit to use a socket (with extension) to get at the obscured bracket nut.
• It is important to do this with a door open and car not locked. With passive locking enabled, the car will want to lock and arm the alarm if all the doors are closed and you have your fob. This is no problem for disconnecting the battery cable, but when reconnected, the theft alarm will sound. If this happens, stop this by pressing unlock with the fob.
• If you have a voltmeter, you can measure the voltage across the battery before disconnecting. If 13.5V or greater, the car is still awake and powering the 12V system from the high-voltage battery and DC-DC converter. If this is the case, you need to wait for this to cease before disconnecting the negative terminal - otherwise the car will not be reset. If the voltage is less than 13.5V, the 12V system is not receiving power for the DC-DC converter, and the negative terminal can be immediately removed.

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Saved me. Car has 300 miles. Stuck in garage. Wife used physical key to climb into car through the back and opened hood so I could perform this reset. Took about 5 mins once I got hoos opened and it worked perfectly.

I'm not sure what caused it but sure hope this isn't a common issue.

 

[bplee]

Thank you for the helpful article. My 2024 Lyriq recently encountered a starting issue, displaying error messages like "Service Battery Fault Vehicle Won't Start" and "Energy Efficiency Data Read Error". Despite having a sufficient 100-mile battery charge, I suspected a computer glitch. Luckily, the incident occurred in my garage, allowing me to attempt charging the car first, to no avail. Discovering your article, I followed the reboot instructions provided, which successfully resolved the issue. It's unfortunate that performing a complete reboot is so complicated, but it saved me from a trip to the dealer and potential towing expenses.

 

[gary.westfield]

How can I clear an infotainment profile password?

 

[RTB]

Steps to do a 'hard' reset of the car's electronics by a 12V battery disconnect and reconnect. Do this in an attempt to resolve issues like modules offline or other functions not working - when a trip to the dealer is not possible or convenient. This is my own approach by performing and documenting the process. Hope this is helpful, and feel free point out any issues or improvements. Steps, photos, and tips below.

Power down and disconnect procedure:

1. Power off vehicle
2. Open drivers door, and leave door open
3. Wait over 5 minutes for car to go to sleep
   1. Can do next steps during this time, just don't disconnect cable until time has lapsed
4. Open hood
   1. Pull hood release (lower left instrument panel) two times
   2. Lift open hood (has hydraulic struts to hold open by itself)
5. Remove central plastic cover
   1. Pull cover up at handhold near windshield (or lift up at front lip) - un-popping 6 plastic clips
6. Remove metal bracket over top of negative terminal
   1. Use a fixed 10mm wrench or socket with extension to remove 2 nuts (one nut is partially under the plastic frame - may be accessed better with a fixed wrench)
   2. Remove bracket
7. Loosen battery negative lead with 10mm socket
8. Pull up on negative battery lead to disengage from battery post
   1. After battery lead removal, insert something non-conductive (cloth or glove) between the battery post and the disconnected lead so it remains disconnected for a period of time
9. Test that vehicle has no power
   1. Try to open rear door, and check interior lights. Confirm no operation / no power.
   2. If power is still present, let vehicle sit for several minutes more. This just means that vehicle wasn't asleep when 12V battery cable was disconnected, and power is still being supplied to the 12V systems by the high voltage battery and DC-DC converter. After a period of time, recheck power until confirmed that vehicle has no power.

Reconnect and power up procedure:

1. Reconnect negative battery cable and tighten nut.
   1. A small spark will sometimes occur and is normal
2. Replace bracket and two nuts above negative terminal portion of battery
3. Replace central plastic under hood cover
   1. Align and apply pressure at each of the 6 snap points until the snaps click back into place.
4. Close hood
   1. Need to lower to about 1 foot, than drop / force down rapidly
5. Enter vehicle and power on
6. All functions should work, but a few things may need to be reset as below...
   1. Tire pressure will be blank until driving about 1/2 mile
   2. Auto-high beams headlight setting should be checked - 'on' setting is not retained
   3. Rear-seat reminder feature should be checked - 'off' setting is not retained
   4. Instrument cluster may prompt you to open and close all windows. It will step you through the process, opening then closing each window. This is to re-calibrate the auto-reverse system. Express-up will not function until the window has been opened then closed.
   5. Depending of software version, there may be other somewhat less obvious settings that aren't maintained. Work through the menus to double check.

Tips:

• You can't reliably disconnect the negative battery lead without removing the metal bracket that is over the top of it. The battery lead can't be raised up sufficiently to clear the battery terminal and not contact the bracket.
• If you are attempting to use a socket for both the bracket nuts and battery terminals, you can't access the inner-most nut off the bracket because the interfering plastic support frame that is partially in the way. To allow a socket to be used, remove the T30 torx screw from the top of the plastic frame. With the screw removed, the plastic support frame can be pulled up and out of the way a bit to use a socket (with extension) to get at the obscured bracket nut.
• It is important to do this with a door open and car not locked. With passive locking enabled, the car will want to lock and arm the alarm if all the doors are closed and you have your fob. This is no problem for disconnecting the battery cable, but when reconnected, the theft alarm will sound. If this happens, stop this by pressing unlock with the fob.
• If you have a voltmeter, you can measure the voltage across the battery before disconnecting. If 13.5V or greater, the car is still awake and powering the 12V system from the high-voltage battery and DC-DC converter. If this is the case, you need to wait for this to cease before disconnecting the negative terminal - otherwise the car will not be reset. If the voltage is less than 13.5V, the 12V system is not receiving power for the DC-DC converter, and the negative terminal can be immediately removed.

View attachment 638494

View attachment 638495

View attachment 638496

View attachment 638566

View attachment 638498

View attachment 638499

View attachment 638500

View attachment 638501

View attachment 638571

View attachment 638572

Great writeup.

 

[Longjohn]

anyone know the part number for the bar that goes across? I opened mine today and the bar wasn't there.

 

[Boatbuilder68]

anyone know the part number for the bar that goes across? I opened mine today and the bar wasn't there.

Do you mean the roller shade that covers the cargo area? It comes standard only on the Sport 3 and Luxury 3 trims.

From the Cadillac Society forum:
The part number is 85157688. MSRP is $168.78. The part description is F-SHADE.

A Google search turned up several others at a lower price.

 

[hightech-guy]

Do you mean the roller shade that covers the cargo area? It comes standard only on the Sport 3 and Luxury 3 trims.

From the Cadillac Society forum:
The part number is 85157688. MSRP is $168.78. The part description is F-SHADE.

A Google search turned up several others at a lower price.

No, he's looking for metal bar that goes across the 12V battery under the hood.

 

[Zymurgy]

Is it part #4 in this diagram?

If so, the part number is 26383428.

 

[Boatbuilder68]

I have no idea. I would go into a dealership parts department and show them that diagram. They can probably find it in their system and order it for you.

If it is on undetermined length back order, go onto the Reddit app in one of the Lyriq subreddits. There are occasional posts there by people who are parting out a wrecked Lyriq. You can do an internal search and send one of them a DM and probably get one that way.

 

[O.C.]

When farting around with wrenches and ratchets around the battery, non-conductive tools are your friend.

My guess is cycling the 12V battery will be simplified on all GM models come 2026.

 

[Jimpilot]

I have no idea. I would go into a dealership parts department and show them that diagram. They can probably find it in their system and order it for you.

If it is on undetermined length back order, go onto the Reddit app in one of the Lyriq subreddits. There are occasional posts there by people who are parting out a wrecked Lyriq. You can do an internal search and send one of them a DM and probably get one that way.

Be very very careful. There are lots of reports of those being scams, even with pictures etc.