Pre collision system malfunction while towing with a 2017 LC (1 Viewer)

[auroracle]

I recently purchased a 2017 Land Cruiser back in May and had been towing by 18 feet teardrop camper weighing around 3500 lbs without any issues for 2 months. I also installed the Redarc trailer brake controller and that has been working flawlessly so far. I recently sold my teardrop for a slightly longer and heavier Lance 1685, 21 feet overall length, and 5500lbs gross trailer weight, still well within the towing limits for the cruiser even with max cargo capacity. I went to pick it up yesterday and as I started to tow it, within a mile or so, the "Pre-collision system malfunction" message showed up asking me to visit the dealer. The Redarc brake controller was also not working with the car brakes but was working when I pushed it directly. I stopped after a few miles and the brake controller issue went away, although it's still very jittery when I let go of the car brakes suddenly, I feel a push by the trailer from the back which was not the case with my previous teardrop. I may have to calibrate the Redarc but I thought it should do that on its own. But now, both the brakes are being engaged at the same time at least. It malfunctioned once again while I stopped in the middle and started but went away when I stopped again. I have absolutely made sure the trailer cord is tightly connected but I don't know if there are any wiring issues inside it. But the brakes always work fine when I press the Redarc controller directly, the intermittent problem is with the proportional part of it. The only 2 differences that I see with my previous camper are one, it's a little heavier and wider, and two, I am using a Husky center line weight distribution hitch with the Lance. My entire 230 miles drive to the dealership was just fine, with no errors but it showed up only when I started to tow. Nonetheless, I towed it back to my place for another 230 miles and it towed like a champ, just that the warning was still there. It's still there now when I am not towing anything. I read a few posts here about rodents chewing up on wires but the fact that there is a clear correlation between towing the new trailer and this issue, I am pretty confused. Is it just coincidental that it showed up right at the time? I have gotten a service appointment this Monday but wanted to see if anyone faced something similar or knows what might be going on. Thanks.

 

[cboyd]

is the new trailer using electric brakes as well, or is it using electric over hydraulic? it is possible you might be pulling too much current depending on the configuration.

you might be better off going to a trailer shop to ensure they are seeing the right signals at your bumper connection before you go to the dealership and they tell you unplug the redarc before they look at it.

a couple of ideas: it is also possible the trailer isn't wired correctly... or the emergency brake battery was low and was drawing too much current. maybe check fuses on the vehicle (consult manual). also I would do a reset/recalibrate on the redarc - if you disconnect the main battery, it will force a reset on the redarc but also might clear the PCS warning too.

a couple of areas to check before going to Mister-T

 

[auroracle]

The new trailer also uses electric brakes. One thing I did a week back was to replace the factory Panasonic battery with an X2 power 27F AGM battery. It did reset a bunch of things after that but never the pre-collision malfunction issue. I will try disconnecting the battery again and see if it shows up or not. Getting a service appointment at an RV store is very hard right now but I will try.

 

[cboyd]

you can always get a trailer pigtail tester at auto parts store to make sure things are good on both the vehicle and trailer - there are ones that plug inline to the trailer and show you if wiring is correct. maybe amazon has some, E-Trailer.com will, but might take a few days to get.

what about the trailer emergency disconnect battery? is it charged?

 

[auroracle]

you can always get a trailer pigtail tester at auto parts store to make sure things are good on both the vehicle and trailer - there are ones that plug inline to the trailer and show you if wiring is correct. maybe amazon has some, E-Trailer.com will, but might take a few days to get.

what about the trailer emergency disconnect battery? is it charged?

Just order this -
Amazon product ASIN B001EOWQY4
Will be delivered tomorrow. Thanks for the suggestion. It's anyways good to have one. Does the emergency brake use a separate battery? I thought they use the same trailer battery, the only 2 batteries I have onboard the trailer are 2 100Ah battle-born lithiums along with a 190 W roof solar which keeps charging the batteries all the time when there is sunlight of course. I picked it up yesterday from eastern Washington with tons of sunlight and the batteries were fully charged.

 

[jacksmom]

Did you ever figure out what's going on? I'm having the same issue with my 2020 GX but only when towing.

 

[TeCKis300]

I recently purchased a 2017 Land Cruiser back in May and had been towing by 18 feet teardrop camper weighing around 3500 lbs without any issues for 2 months. I also installed the Redarc trailer brake controller and that has been working flawlessly so far. I recently sold my teardrop for a slightly longer and heavier Lance 1685, 21 feet overall length, and 5500lbs gross trailer weight, still well within the towing limits for the cruiser even with max cargo capacity. I went to pick it up yesterday and as I started to tow it, within a mile or so, the "Pre-collision system malfunction" message showed up asking me to visit the dealer. The Redarc brake controller was also not working with the car brakes but was working when I pushed it directly. I stopped after a few miles and the brake controller issue went away, although it's still very jittery when I let go of the car brakes suddenly, I feel a push by the trailer from the back which was not the case with my previous teardrop. I may have to calibrate the Redarc but I thought it should do that on its own. But now, both the brakes are being engaged at the same time at least. It malfunctioned once again while I stopped in the middle and started but went away when I stopped again. I have absolutely made sure the trailer cord is tightly connected but I don't know if there are any wiring issues inside it. But the brakes always work fine when I press the Redarc controller directly, the intermittent problem is with the proportional part of it. The only 2 differences that I see with my previous camper are one, it's a little heavier and wider, and two, I am using a Husky center line weight distribution hitch with the Lance. My entire 230 miles drive to the dealership was just fine, with no errors but it showed up only when I started to tow. Nonetheless, I towed it back to my place for another 230 miles and it towed like a champ, just that the warning was still there. It's still there now when I am not towing anything. I read a few posts here about rodents chewing up on wires but the fact that there is a clear correlation between towing the new trailer and this issue, I am pretty confused. Is it just coincidental that it showed up right at the time? I have gotten a service appointment this Monday but wanted to see if anyone faced something similar or knows what might be going on. Thanks.

How did the LC look in terms of squat once you got the trailer all hitched up? Thinking out loud but I wonder if there was so much squat, or the nose was pointed too far up that the pre-collision radar/camera gave up, hence the malfunction?

That doesn't quite explain the tow controller though. I don't own a redarc and I've heard they're self calibrating, but it maybe for the same reason that it needed to re-calibrate it's own internal accelerometers to account for the rigs attitude?

If the rig is squatting too heavily, solution is to apply more tension on the WD bars.

 

[LC Mike]

I recently purchased a 2017 Land Cruiser back in May and had been towing by 18 feet teardrop camper weighing around 3500 lbs without any issues for 2 months. I also installed the Redarc trailer brake controller and that has been working flawlessly so far. I recently sold my teardrop for a slightly longer and heavier Lance 1685, 21 feet overall length, and 5500lbs gross trailer weight, still well within the towing limits for the cruiser even with max cargo capacity. I went to pick it up yesterday and as I started to tow it, within a mile or so, the "Pre-collision system malfunction" message showed up asking me to visit the dealer. The Redarc brake controller was also not working with the car brakes but was working when I pushed it directly. I stopped after a few miles and the brake controller issue went away, although it's still very jittery when I let go of the car brakes suddenly, I feel a push by the trailer from the back which was not the case with my previous teardrop.

I have 2018 LC and just put a new suspension and brake system on my trailer and had the same experience. It is still about 3500#, but the Redarc does what you experienced. Haven't done any reset, but it seems to be getting less pronounced as I drive on it more.

 

[CharlieS]

The Redarc can take a significant number of brake applications to recalibrate.