Hi! I recently purchased a 2020 GX specifically for towing. I picked my camper up for the first time Wednesday (16ft Airstream, dry weight 3,000lbs) and within 2-3 miles I got a PSC Malfunction notice. I took it to the dealer the next day and they couldn't see anything wrong so they cleared the codes. Saturday, I went to move the camper again, and within 2-3 miles again, I got the warning. I went to the dealership with the camper and again they found nothing, aaa technician rode with me for about 5 miles and the warning didn't return, so we hoped it was solved. Nope. About 28 miles on the interstate with no issues, got off the highway and I got the warning again. I am a super frustrated to say the least. Has anyone experienced this? Any ideas where to start? I have an appointment at an RV shop Thursday to make sure I adjusted the hitch setup correctly.

 

Did they note what codes they cleared?

There is a mentioned in owners manual that you may need to disable PCS while towing another vehicle. Is this vehicle reference in owner's manual a trailer? I can't say for sure

https://lexusgxor.com/_media/general...ers_manual.pdf

Page 237

 

I would think it only makes sense to disable PCS so that the sensors don't go haywire, no?

 

The PCS uses forward facing sensors and the camera to detect objects, there is no way a trailer should trigger the system. The manual says you need to disable when "being towed" i.e following another vehicle closely, not towing. Is there anything covering or over the front area on your GX? bug screen, plastic film over camera, etc

 

Ah, I stand corrected.

 

Excerpt from the TIS, Toyota Information System section on 2020 GX 460 PCS:

(a) Make sure to turn the pre-collision system off in the following situations, as it may operate unexpectedly or may not operate when necessary.

• When the vehicle is being towed
• When the vehicle is towing another vehicle
• When transporting the vehicle via truck, boat, train or similar means of transportation
• When the vehicle is raised on a lift with the engine running and the tires are allowed to rotate freely
• When inspecting the vehicle using a drum tester such as a chassis dynamometer or speedometer tester, or when using an on vehicle wheel balancer
• When a strong impact is applied to the front bumper or front grille, due to an accident or other reasons
• If the vehicle cannot be driven in a stable manner, such as when the vehicle has been in an accident or is malfunctioning
• When the vehicle is driven in a sporty manner or off-road
• When the tires are not properly inflated
• When the tires are very worn
• When tires of a size other than specified are installed
• When tire chains are installed
• When a compact spare tire or an emergency tire puncture repair kit is used
• If equipment (snow plow, etc.) that may obstruct the millimeter wave radar sensor assembly or forward recongnition camera is temporarily installed to the vehicle

 

I'm assuming trailers count then? I can't imagine how the GX would distinguish between towing a vehicle via a trailer or not?

 

I remember reading that the trailer towing ratings for the Honda Pilot (2015?) was one value
for trailers and another for boats, presumably on a trailer. Wind resistance apparently?

 

The PCS on any vehicle goes haywire when left on while towing. Reason being the movements of the vehicle are larger due to the weight of the trailer. This causes the sensors to detect things like trees, signs, guardrails and other fixed objects.

 

I have towed a trailer with PCS on and no issues. Its actually been helpful im two situations where stopped traffic ahead surprised me and the GX. Lights flashed belts tightened and nothing bad happened (minus being scared 💩less)

Question which package do you have? i.e do you have rear bags? do you use a hitch stabilizer? how does the GX look when attached? (saggy in the back?)

I could see if the GX is sagging in back the front sensor may not be able to see straight ahead, but more of an upward angle.

I also use the radar cruise while towing and it does a fine job on long highway stretches (despite owners manual advising against)

 

There was never any mention of what, if any, code was there. At one point a steering angle code came up. Not sure if the two are related. I have not turned off PCS e before towing because I haven't remembered to, however I have to friends who tow; one has the exact same set up as me and one has a larger camper, neither turn the PCS off and neither have had a problem. 🤷🏻‍♀️

 

Nothing is covering the sensor, we have checked so many times. This has now happened 6 times.

 

I don't know how to reply on this thing, so hope I'm doing it correctly. 🤦🏻‍♀️ it is the premium package. I do not have rear bags, but do have a weight distribution and sway hitch which they are now blaming for the problem as well as my wireless brake controller. The photo below isn't the greatest because the driveway slants a bit at the end, but there really isn't any sag to speak of.

 

Try going on a short drive with the wireless brake controller turned off to see if that may be the cause. I tow a 19' with a weight distribution hitch and a Redarc wired brake controller. Mine is the executive which has the air suspension but I have never had the PCS go off.

 

the very first time it happened I had forgotten the brake controller so I just plugged the 7-pin right into the receiver. It has happened 3 times with the brake controllers and 3 times without. The dealership is now questioning my hitch (equalizer) being the issue.