Welcome to Tesla Motors Club
Discuss Tesla's Model S, Model 3, Model X, Model Y, Cybertruck, Roadster and More.
Register

condition detected with a vehicle controller

This site may earn commission on affiliate links.
Hello, this morning I went to drive my 2021 Model Y and found the following error message: "condition detected with a vehicle controller". The error code is "vcfront a552". I got it scheduled for service, but not for about 3 weeks. Does anyone know what this is and if it's serious? Can I drive the vehicle safely until I get it fixed? Thanks.
 
Just message the service team about your appointment with those questions. I received a message like that one morning (I don't remember what my message said, but it turned out they needed to replace a data cable). I messaged the service team with similar questions and they answered within a half a day.
 
Hello, this morning I went to drive my 2021 Model Y and found the following error message: "condition detected with a vehicle controller". The error code is "vcfront a552". I got it scheduled for service, but not for about 3 weeks. Does anyone know what this is and if it's serious? Can I drive the vehicle safely until I get it fixed? Thanks.
I have the same message on my 2021 Model 3 LR…..appointment set on April 4.
 
Really confused because the car has been garaged all winter, plugged in, and only on the road twice for short local trips. This car has never been on a snowy road and only 1,700 miles on it.
 
I have the same issue with my Model Y. It appears to only get the vcfront a552 error when the trailer is hooked up, but usually only after it has been connected for an extended time. The SC told me they believe the vcleft controller is encountering a problem related to the wiring to my trailer brake controller. The brake controller is a Tekonsha P3 and seems to be working perfectly. There is no evidence of heating or other issues with the Tesla-supplied wiring pigtail, or the brake controller wiring.
I have been monitoring the brake controller when the trailer is hooked up and not seeing any errors, over voltages, or overcurrents. The trailer brakes are working properly.
So, I'm unconvinced the controller is the problem, though I admit there seems to be a correlation between hooking up the trailer and the error eventually being displayed.
I used this controller for 9 months or so to tow my camping trailer over 3000 miles before the error started popping up.
Hoping someone will have ideas for further troubleshooting. My plan is to tow the 2000 lb trailer without the brake controller hooked up to see if the problem occurs in that situation, but won't have a chance to test this for another 3 weeks or so.
 
I got this message yesterday in my Model Y (factory tow package, P3 brake controller) and thought I would share my experience as this thread was one of the ones that came up when I searched for "Condition detected with a vehicle controller vcfront_a552". I had just got home after towing my camper in a rain storm. After the rain stopped I went outside to disconnect the trailer and move the car into the garage. The connector was a little wet when I did this. When I got into the car to move it, the message appeared. I suspected that I might have got some water into the 7-pin trailer connector when I disconnected the cable, so I carefully used a paper towel on the end of a small dowel to try and dry out the pins. I then moved the car back into the garage hard reset it (actually it was due for a firmware update for the last couple of days while we were on our trip). About an hour later I went back out to the car and it was as if nothing had ever happened.

My suspicion is that that little bit of water that got into the connector while I was disconnecting it might have shorted between the pins, prompting the controller error. Perhaps there was a poly fuse inside that did its job and reset after everything was dry and back to normal. After the reset imposed by the firmware update, and because everything was dry, all was well again. Anyway, I've been back to driving the car today with no further issues. Hopefully other folks that run into this issue have as easy of a time as I did.
 
  • Like
Reactions: fly4fun
I got this message yesterday in my Model Y (factory tow package, P3 brake controller) and thought I would share my experience as this thread was one of the ones that came up when I searched for "Condition detected with a vehicle controller vcfront_a552". I had just got home after towing my camper in a rain storm. After the rain stopped I went outside to disconnect the trailer and move the car into the garage. The connector was a little wet when I did this. When I got into the car to move it, the message appeared. I suspected that I might have got some water into the 7-pin trailer connector when I disconnected the cable, so I carefully used a paper towel on the end of a small dowel to try and dry out the pins. I then moved the car back into the garage hard reset it (actually it was due for a firmware update for the last couple of days while we were on our trip). About an hour later I went back out to the car and it was as if nothing had ever happened.

My suspicion is that that little bit of water that got into the connector while I was disconnecting it might have shorted between the pins, prompting the controller error. Perhaps there was a poly fuse inside that did its job and reset after everything was dry and back to normal. After the reset imposed by the firmware update, and because everything was dry, all was well again. Anyway, I've been back to driving the car today with no further issues. Hopefully other folks that run into this issue have as easy of a time as I did.
I've been wondering the same thing on my Tesla as the first times I encountered the problem I was driving through slush from snowstorms and thought maybe I got water in the connection. However, the most recent time, I was careful to make sure the connector pins were completely dry before connecting and I was towing on a dry day. The error popped up about 20 minutes or so after I had parked the car at a camp site and had got back in to move it a short distance.
After disconnecting the trailer, the error cleared within a few hours.
I'm wondering if the problem could be related to the Tesla recharging it's 12V battery while the car is sleeping. Perhaps the 12V battery is getting drawn down more than usual during that recharge cycle by the connection through the brake controller, though it doesn't seem likely. This is just some speculation on my part after reading on this forum about other VCFRONT alerts that seem similar, but not exactly the same.
 
Had it happen today. MYLR, Tekonsha P3 brake controller.

Parked for a couple of hours with the 7 pin connector plugged in, car charging with wall connector, Tab 320S connected to shore power.

The alert went away after several hours after I disconnected the the camper and charged the car with the wall connector.
 
Here's some more info on my experiences. Hope it can help someone figure out why they are getting this alert.
Disclaimer: I'm no expert on trailer or Tesla electronics or wiring issues. Just spent a lot of time reading up on things to try to understand what's going on with my rig.

I've had my Model Y back to the Service Center three times to troubleshoot this alert.
Here's what I've learned and what I plan to do as a work-around to avoid the problem:
It does seem consistent that it happens after the car has been shutdown for a while with the trailer attached.
The brake controller, also a Tekonsha P3 in my case, and the brake controller wiring have been exonerated. The problem occurs even when the brake controller is disconnected.
The SC, I think has done all it can. They replaced the VCFRONT body controller with no effect, and have done extensive checks of the wiring and the logs. They even tested it with a trailer they had at the SC, but couldn't recreate the problem.
They did convince me that the DC-DC converter in the car and the car's 12v battery are not likely to be at fault.
The problem seems to be an overcurrent that trips an Efuse in the Tesla, in my case, while the car is shutdown or when it is waking up. The Efuse trip is detected during self-test when the car wakes up, and the alert is presented. The expanded alert, according to the SC writeup is VCFRONT_a552_eFuseSelfTestFailure

The Efuse apparently protects a number of things and is not specific to a particular wire in the 7-pin connector. It is tripped by an overcurrent which could be a quick rush of current either too or from the trailer. There are no diodes in the wiring to the trailer, so the current could come from the trailer's battery, or likewise, there could be a drain going to the trailer's battery, or the lights.

I haven't gotten a clear answer on what amount of current will trip the Efuse, but have the impression is might be well under 15 amps. It is my understanding that the Efuse trips much faster than a conventional fuse or circuit breaker, so it might be a very short rush of current that might not affect other tow vehicles.

Overall, my impression is that the Tesla is sensitive to current fluctuations that might not affect other tow vehicles. I think the most likely source of the fluctuations in my case are the trailer battery having a higher or lower charge state and either backfeeding the Tesla or causing a drain exceeding the threshold for the Efuse. Note: On my trailer the battery is wired directly thru to the power pin (Battery power) in the 7-pin connector.

I've never had the problem occur while driving, over 3500 miles with the same trailer, just while completely shutdown with the trailer still attached.

The SC suggested that when I shutdown, I disconnect the electrical cable to the trailer, which seems reasonable as long as I remember to always connect it again before continuing my trip!

It seems likely to me that the trailer's battery is what the Tesla doesn't like. The lighting could have some kind of issue, but I'm doubtful of that. All the trailer lighting is checked before each trip and all are working fine. Also, I don't have anything internal, like a fridge, running on 12v on the trailer while it is connected to the car.

My plan is to pull the inline fuse on the battery + wire when I shutdown with the car still attached, and stick it back in before continuing. This effectively disconnects the trailer battery from the car, and the trailer.

I'm also considering installing a diode on the Battery+ lead of the 7-pin connector cable to prevent any current from flowing back into the car from the battery and see if I can get away with leaving the battery fuse installed while the car is shutdown.



To be continued...
 
  • Informative
Reactions: coleman567
...continued.
I decided to simply cut the power lead (Battery+ lead) of the 7-pin connector cable, and install an empty inline fuse holder. This isolates the Tesla from the trailer's battery completely. If I change my mind and want to hook it back up again I just need to install a fuse in the fuse holder to reconnect.

I'm cautiously optimistic that this step has fixed the issue. I've been towing the trailer and leaving it connected long enough for the car to completely shut down. After 6 cycles like this, I haven't encountered the Efuse trip at all.

Downside of doing this is the trailer battery is no longer being charged by the car while driving. I'm intending to install a solar panel and controller on the trailer to keep the battery charged up.