AC turning off and on constantly

[hydbob]

Should be fixed in the next update.

 

[Gap323]

I will also mention that I lost high reservation. It reverted to standard. Not sure when that happened. Was wondering why it was not stopping as it used to on my trip, although I still got 4.1 miles per kw with standard regen.

I literally drove on the highway yesterday I had 430 miles of charge. 80 miles cruise control, a/c level one, stuck in 1 lane. My miles per kw did not pass 2.9. I drove 180 miles total my charge shows 149 miles remains. Not sure if that’s how it’s supposed to. This is my first EV.

 

[Bunnylebowski]

I literally drove on the highway yesterday I had 430 miles of charge. 80 miles cruise control, a/c level one, stuck in 1 lane. My miles per kw did not pass 2.9. I drove 180 miles total my charge shows 149 miles remains. Not sure if that’s how it’s supposed to. This is my first EV.

19” wheels? Are your tire pressures correct? Exterior temperature? Elevation? All of those effect efficiency a lot.

 

[Bunnylebowski]

Oh, and to stay on topic I’ve also had the AC shut off and turn back on, it’s like it’s recycling itself or something. Usually comes back on in 10 seconds. A few times it’s shut off completely and I’ve had to manually turn it back on. I find the rear seat AC always defaults to off, and will randomly shut off requiring you to turn it back on manually.

 

[hmp10]

10-15 minutes is new. Everyone reporting here is no more than a minute. Send CS a report!

Mine went off for an extended period shortly after the Pilot Screen froze and the right panel of the Glass Cockpit blacked out. It did not come back on even after I pulled off the road and rebooted. It finally returned the next morning after an overnight park. It was one of the reasons the car had to go back in to a service center.

 

[Mr_rhythm]

All of the various issues sound like symptoms of a major electrical layout problem. Random surges or cuts to the power causing various systems to go wonky. And the 12v issue is obviously the most critical since you completely lose the ability to drive. I have to believe all these things are related and just manifesting in different ways. How else could they manage to have problems in basically every subsystem in the vehicle?

 

[DaveyBoyGT]

Oh, and to stay on topic I’ve also had the AC shut off and turn back on, it’s like it’s recycling itself or something. Usually comes back on in 10 seconds. A few times it’s shut off completely and I’ve had to manually turn it back on. I find the rear seat AC always defaults to off, and will randomly shut off requiring you to turn it back on manually.

I was thinking that maybe this is just a normal recycling of the AC compressor to maintain a thermostatic temperature in the cabin space. For those experiencing condition, is the AC actually shutting off (indicator lights), or is this just a normal compressor cycling?

 

[Bunnylebowski]

All of the various issues sound like symptoms of a major electrical layout problem. Random surges or cuts to the power causing various systems to go wonky. And the 12v issue is obviously the most critical since you completely lose the ability to drive. I have to believe all these things are related and just manifesting in different ways. How else could they manage to have problems in basically every subsystem in the vehicle?

That’s possible, but it makes me wonder then why are things usually cured by a reboot? Of course @hmp10 couldn’t troubleshoot the AC cuz his pilot panel went out. Other solutions could be to park and lock the car then try and remote set the climate system from the phone app. I just think if it was a hardware/wiring problem then it would just fail and that would be that. Doesn’t make sense to me that resetting the software would somehow change the electrical layout, although software can dictate open/closed circuits. I’m more suspicious that the underlying software which controls how power is distributed to various modules in the vehicle is bad. Given they did a recall on every car for a wiring harness issue that affected almost no vehicles, I’d think if this was a wiring problem we’d have seen another recall.

 

[Bunnylebowski]

I was thinking that maybe this is just a normal recycling of the AC compressor to maintain a thermostatic temperature in the cabin space. For those experiencing condition, is the AC actually shutting off (indicator lights), or is this just a normal compressor cycling?

Most of the time for me it’s been just cycling and comes back 10 seconds later. A few times though it just shut off completely and the Pilot panel reflected that it was turned off, so I just pressed the power button for the AC on the screen and it came right back and worked fine.

 

[DaveyBoyGT]

All of the various issues sound like symptoms of a major electrical layout problem. Random surges or cuts to the power causing various systems to go wonky. And the 12v issue is obviously the most critical since you completely lose the ability to drive. I have to believe all these things are related and just manifesting in different ways. How else could they manage to have problems in basically every subsystem in the vehicle?

Not to trivialize this problem, but the problem may be as simple as a random group of poor solder joints on relevant circuit boards in the Wonderbox and other locations. I have repaired a number of circuit boards in an ICE car this way. Maybe Lucid needs to check their circuit boards to at least rule that out as a cause of the problems.

 

[DaveyBoyGT]

Most of the time for me it’s been just cycling and comes back 10 seconds later. A few times though it just shut off completely and the Pilot panel reflected that it was turned off, so I just pressed the power button for the AC on the screen and it came right back and worked fine.

Sounds like a control problem with the compressor cycling. If there is too much time between cycling of the compressor (such as when outside temp is moderate) that the system senses the AC is not needed and shuts down the AC to preserve energy.

 

[Mr_rhythm]

Not to trivialize this problem, but the problem may be as simple as a random group of poor solder joints on relevant circuit boards in the Wonderbox and other locations. I have repaired a number of circuit boards in an ICE car this way. Maybe Lucid needs to check their circuit boards to at least rule that out as a cause of the problems.

Aye, when I say “major” something like poor solder joints would suffice. I mean along the lines of consistent inconsistency in one of their electrical system components. Bunny definitely has a point about a reboot fixing it, which would lend itself back to software, but the randomness of so many different things feels like gremlins to me.

 

[CLTGT]

Most of the time for me it’s been just cycling and comes back 10 seconds later. A few times though it just shut off completely and the Pilot panel reflected that it was turned off, so I just pressed the power button for the AC on the screen and it came right back and worked fine.

Mine actually turns off and I just hit the "AC" button again on the screen.

 

[martinmeyer]

I'm gonna step in here with the software engineering view. Reports of the HVAC shutting off periodically for 10 seconds sound to me like a watchdog timer is being missed. Maybe they have some mechanism designed as a failsafe to ensure the HVAC turns off if the car seems to be turned off. Maybe the implement it by periodically telling the HVAC controller "stay alive!". Maybe sometimes they miss it, or the message delivery is delayed. The HVAC turns off, then either stays off or resumes after the next message arrives (depends on the reason a message was missed). For comparison, Tesla seems to do the opposite in my Model S: when I reboot the MCU, the HVAC stays on for about a minute then shuts off. I think the MCU is using a watchdog timer to ensure the HVAC doesn't remain on indefinitely when the car is otherwise offline.

The bit about it sometimes not coming back online is interesting, and might aline with some of the other reported problems. Alexa stops working and won't come back until reboot? Audio stops playing from Tidal and won't come back? Lots of miscellaneous things seeming to halt working and sometimes returning all at once? This sounds to me like a resource deadlock problem. Some of the aspects of it seem like they didn't use a proper threating model to isolate services, or maybe didn't properly protect some resources from multiple concurrent accesses. Incorrect use of threading can explain a ton of the bugs I've seen described with the car.

 

[LucidNC]

I'm gonna step in here with the software engineering view. Reports of the HVAC shutting off periodically for 10 seconds sound to me like a watchdog timer is being missed. Maybe they have some mechanism designed as a failsafe to ensure the HVAC turns off if the car seems to be turned off. Maybe the implement it by periodically telling the HVAC controller "stay alive!". Maybe sometimes they miss it, or the message delivery is delayed. The HVAC turns off, then either stays off or resumes after the next message arrives (depends on the reason a message was missed). For comparison, Tesla seems to do the opposite in my Model S: when I reboot the MCU, the HVAC stays on for about a minute then shuts off. I think the MCU is using a watchdog timer to ensure the HVAC doesn't remain on indefinitely when the car is otherwise offline.

The bit about it sometimes not coming back online is interesting, and might aline with some of the other reported problems. Alexa stops working and won't come back until reboot? Audio stops playing from Tidal and won't come back? Lots of miscellaneous things seeming to halt working and sometimes returning all at once? This sounds to me like a resource deadlock problem. Some of the aspects of it seem like they didn't use a proper threating model to isolate services, or maybe didn't properly protect some resources from multiple concurrent accesses. Incorrect use of threading can explain a ton of the bugs I've seen described with the car.

Agreed. If true, then the troubling thing is that these issues seem to have existed for some time; indicating a difficult fix/patch. I fear that a software re-design is needed. If so, I hope that is underway. Of course, that'll bring its own set of potential new issues. Any idea what their pre-release/beta testing is like?

 

[hydbob]

Agreed. If true, then the troubling thing is that these issues seem to have existed for some time; indicating a difficult fix/patch. I fear that a software re-design is needed. If so, I hope that is underway. Of course, that'll bring its own set of potential new issues. Any idea what their pre-release/beta testing is like?

Software redesign is already in the works and supposedly to be released this year so...stay tuned!

 

[Gap323]

19” wheels? Are your tire pressures correct? Exterior temperature? Elevation? All of those effect efficiency a lot.

I have the 21, tire pressure we’re good. Exterior was surprisingly cool, 70 degrees. Elevation wasn’t going up a mountain but I understand what your saying.

 

[Gap323]

Oh, and to stay on topic I’ve also had the AC shut off and turn back on, it’s like it’s recycling itself or something. Usually comes back on in 10 seconds. A few times it’s shut off completely and I’ve had to manually turn it back on. I find the rear seat AC always defaults to off, and will randomly shut off requiring you to turn it back on manually.

Yes mine has done that before, where if I don’t mess with the switches it won’t turn back on. And I have timed it, maximum I went was 15 minutes where I did not touch anything and it came back on. Super annoying.

 

[Gap323]

Sounds like a control problem with the compressor cycling. If there is too much time between cycling of the compressor (such as when outside temp is moderate) that the system senses the AC is not needed and shuts down the AC to preserve energy.

That makes absolute sense, that’s what I was thinking as well, although the interior is not at the certain level I have it programed at. I feel like the sensor senses it is so it turns off, but that’s just my thought.

 

[3rdEV]

Oh, and to stay on topic I’ve also had the AC shut off and turn back on, it’s like it’s recycling itself or something. Usually comes back on in 10 seconds. A few times it’s shut off completely and I’ve had to manually turn it back on. I find the rear seat AC always defaults to off, and will randomly shut off requiring you to turn it back on manually.

The back seat air in my 2021 MSLR may or may not default to off
Have to check it every time I start dog mode (back seat carrier).
Frustrating.