[Travis959]

Yesterday while driving I got a notification on the dash about servicing the Tire Monitoring System and I noticed the front passenger TPMS was blank. Then it came up again a few minutes later and now the back passenger TPMS was showing blank. I turned the car off and turned it back on and they came back on and the message went away.

While driving back home, the same sensors go out again, so it seems to be after driving around 20-25 minutes they go out. After I got home, I check OnStar and it only shows blank for the front passenger. I pull the codes and it shows:

U0073
U0100
U0101

This morning on the way to work, they both came back on and the message went away. My trip to work is only 10 minutes however so it isn't long enough to make them go out again.

However after about 4 minutes of driving, manual mode for the AT switches back to "D" and the check engine light comes on. After that I couldn't put it back in manual mode, and once I got on the highway I found I was stuck in the gear I was in, which was 4th. Fortunately, I didn't have to go far and it was a low enough gear to get through a couple stoplights.

I plan on making a dealer appointment sometime today, but has anybody seen something like this? Is this most likely electrical issues? The only thing I've done recently was plastidip my wheels 3 weeks ago and on Thursday of last week, I put in a rear dashcam. My front dashcam has been in since 2018 so it's been hardwired since then so I didn't touch any car wiring unless I perhaps unseated something when I pushed the cable up into the headliner? There was quite a bit of cable I had to push up in the rear section of the headliner since the cable was too long.

[zirad54]

Before anything else, check your battery. A low battery will cause all kinds of electrical issues. if your battery is over 3 years old, you may want to consider replacing anyway. I have found that there is usually no "warning", one day it is working fine then all of a sudden, click, click.

[Travis959]

Dealership stated it's because of the dashcam being hardwired and that it's confusing the system and causing it to go into limp mode? I thought limp mode was just reduced power, not locked into one gear?

Like I said the front cam has been hardwired since 2018 shortly after I got the car, but the rear cam was added a few days ago. I did upgrade to this 2.ch camera back in December however. The camera is currently hardwired to the passenger air bag light in the top console.

I guess it's possible since the rear camera was just added so maybe that took it over the power limits. I guess I'll unplug those and see if it still does it. Perhaps the battery needs to be replaced as well.

If it helps, I'm using a Viofo A129 now, upgraded from a Viofo A119: https://www.amazon.com/VIOFO-STARVIS...dp/B07DL8MS1T/
This is the hardwire I used: https://www.amazon.com/gp/product/B00MH4ZVHO/

[Travis959]

Tested battery and saw no problems and I haven't had any issues since unplugging the rear camera. According to research online, front + rear camera only pull 3.8 volts.

Not sure what the next step is to figure out the issue. Only thing I can think of is maybe the hardwire kit can't handle the extra voltage once the second camera is added.

[zirad54]

Originally Posted by Travis959

Tested battery and saw no problems and I haven't had any issues since unplugging the rear camera. According to research online, front + rear camera only pull 3.8 volts.

Not sure what the next step is to figure out the issue. Only thing I can think of is maybe the hardwire kit can't handle the extra voltage once the second camera is added.

I would look into the amp draw, not volts.

[Travis959]

So, I've completely reinstalled the dash camera setup so it draws power from the fuse box in the trunk. Unfortunately this didn't solve the problem though. I haven't gotten the CEL message again, but the TPMS sensor still goes out fairly often.

If I take the USB cable going from the front camera to the back camera and take it out of the headliner, then the problem seems to go away. So most likely the USB cable is causing some kind of interference with a module that I assume is either near the rear view mirror or perhaps somewhere near the back window as there was a lot of excess cable that had to be shoved up there. Does anyone know if there is a TPMS module above the headliner and where it is?

[ember1205]

Originally Posted by Travis959

Tested battery and saw no problems and I haven't had any issues since unplugging the rear camera.

Exactly how did you test? You need to measure voltage on the battery "at rest" and you may also need to have a meter measuring in-line amp draw both while the car is off and while it's running.

The dealership stating that the limp mode is because of the camera is likely complete BS and them just looking for a reason to deny any warranty service (or just lack of interest in trying to actually determine the problem).

Did you try putting a battery tender/charger on the car to see what it showed?

Having ANYTHING hardwired should be connected in a manner that ensures the device is only operational when the car is on. Any dash cam with a "parking mode" should be able to store power either in an internal rechargeable battery or capacitors to ensure that it can capture footage while power is off.

As has been mentioned... the batteries on these cars are pretty heavy duty because the car needs the power. And, anything less than 'perfect' operational state means that there is risk of odd problems. Return the car to an "as stock as possible" configuration, get your battery in proper working order (test, remediate, and validate), and see what happens from there.

[Rock-It Man]

This is probably not a battery voltage problem.

You can't just plug devices into sensor circuits. These use low voltage signals to communicate the status of sensors. If you tap into them, all sorts of data mayhem ensues.

[TJay74]

The dealer are always quick to blame dash cameras as it is a easy way for them to not have to spend hours on electrical gremlins.

As said though, anything electrical that is not parts of the cars computer system needs to be directly plugged into the battery system and not thru any of the fuse blocks as it can cause some issues in the CANBUS system.

[ember1205]

Originally Posted by TJay74

The dealer are always quick to blame dash cameras as it is a easy way for them to not have to spend hours on electrical gremlins.

As said though, anything electrical that is not parts of the cars computer system needs to be directly plugged into the battery system and not thru any of the fuse blocks as it can cause some issues in the CANBUS system.

Wiring direct to the battery is fine as long as you want constant power. If you want to do that for a Dash Cam, the camera had better be smart enough to figure out on its own that the car is off or it's going to be recording constantly and will drain the battery quickly.

There are plenty of ways to wire into the fusebox or tap existing wires that won't interfere with the CANBUS communications... Use a direct wire to the battery and connect a NO relay to get power from a switched fuse. That way, you don't interfere with anything on the CANBUS or draw any additional current/voltage that may be monitored, but you also get a way for the device to power down when the car is off.

[Travis959]

Unfortunately, I don't believe it has anything to do with the way the dashcam is powered. It only happens when the rear camera is powered on and the cable to the rear dashcam is placed inside the headliner. Without these two things being true, I haven't experenced any TPMS errors or any other issues.

Regardless, I did buy a new hardwire kit specifically for this camera and wired it up to the recommended fuses in the trunk via fuse taps to see if that would resolve the issue.

The other thing is when the TPMS service message comes up, as long as the rear camera is plugged in, the TPMS light will blink on the dash and the TPMS for the front passenger wheel will stay blank. A few seconds after I unplug the rear camera cable, the TPMS comes back online and the error goes away.

All of that, at least to me, means there has to be something near the cable inside the headliner that the cable is interfering with through perhaps poor shielding on the usb cable itself. I believe my next best option is to see if perhaps a ferrite choke on the usb cable will help in any way.

[ember1205]

Originally Posted by Travis959

Unfortunately, I don't believe it has anything to do with the way the dashcam is powered. It only happens when the rear camera is powered on and the cable to the rear dashcam is placed inside the headliner. Without these two things being true, I haven't experenced any TPMS errors or any other issues.

Regardless, I did buy a new hardwire kit specifically for this camera and wired it up to the recommended fuses in the trunk via fuse taps to see if that would resolve the issue.

The other thing is when the TPMS service message comes up, as long as the rear camera is plugged in, the TPMS light will blink on the dash and the TPMS for the front passenger wheel will stay blank. A few seconds after I unplug the rear camera cable, the TPMS comes back online and the error goes away.

All of that, at least to me, means there has to be something near the cable inside the headliner that the cable is interfering with through perhaps poor shielding on the usb cable itself. I believe my next best option is to see if perhaps a ferrite choke on the usb cable will help in any way.

So, your rear camera is hardwired and the wiring passes through the headliner? Let me guess.. On the passenger side of the car?

What are the chances that there is a radio frequency interference from that wiring that is blocking out the signal from the TPMS sensors on that side of the car?

Better yet, what are the chances that the WiFi in the rear camera is knocking out the signal on that side of the car? You may not have a "fix" here if it's the WiFi. It -shouldn't- be the WiFi as that should be on a different frequency from that of the TPMS (likely 315MHz).

[Travis959]

It was originally on the passenger side, but I moved the cabling to the driver side. TPMS that goes out has been still the passenger side so far.