pre-collision system malfunction - visit dealer

There is a amber PCS off light that is lit all the time yes

 

I had a very similar situation after installing the Eibach 2" lift & Pro grill (figured the height change would offset each other) on my 2020 about 2 years ago. All the dash lights were on. The alignment took care of the zero point recal reset and that fixed 1 light. Took it to the dealer to reset the TSS only option. They had it for 4 days, the tech went through the process... new TSS harness, new TSS sensor, etc but still had the error. Day 4 they brought the senior tech over, they even had me come in to unlock/remove my trailer hitch so no obstructions. They had plump bobs hanging from all sides of the truck and a weird graph chart thing on the wall in front. He fixed it in a just a few minutes after that. He said all the angles for the yawl, axis, etc needed to be set properly prior to resetting it.
Bottom line - it can be fixed by the dealer, looks like a lot of work to me so maybe that's why some say no??

 

There is a TSB for the radar sensor to be replaced because it can get water inside and eventually cause malfunctions. So anything related to that center "garnish" sensor leaking or moisture inside can be done via TSB.

 

I wonder why the Lane Departure and Auto Headlight would be related to the radar in the grille? Why three separate codes?

 

I have no sensors in my rear or front bumpers (because I replaced them with actual steel) and I still have lane departure available. I keep it turned off since it's so annoying when I drive home after having a few drinks. (j/k) : - )
Have never played with the auto headlights but those are triggered by the dashboard light sensors near the dash speakers I believe. Don't know what to tell you about the codes the ECU throws, those are created from the minds of Japanese engineers...

 

Might I have read somewhere that led brake lights when they fail can cause this? I thought I saw this in another thread somewhere???

 

Interesting. Someone else asked if I had after market headlights and taillights. I guess it would be to straightforward to have a separate code for taillights.

 

It could be intentional, not sure. These vehicles are getting so "Control-Module" centric, that I imagine there's a lot of software programming / code, and well, sometimes all paths through that software are NOT tested. Bulbs with filaments fail nicely, as an open circuit. LEDs sometimes fail open, closed, or high resistance. I like how others here always ask posters, what mods, what was the last thing changed? That's a good place to start.

 

That’s the thing. The truck was sitting in the Park ‘n Jet for four days. It’s heavily moded, but that was 50,000 miles ago. No recent changes.

 

I'm having seemingly random TSS pre-collision issues. Usually start after hour + driving, then goes in and out (sometimes warning is on for only 3 minutes, others for 25 minutes then goes off again?), again, randomly. What are the symptoms to indicate "water"? Mine is a 2021 - I couldn't find the TSB thru google - does it apply to '21's still?

 

Mine started doing this out of nowhere trucks pretty new got it lifted at the dealership with the factory lift and pro grille about a month after I bought it back in August and it just now started giving me the warning I haven't been in any wrecks

 

Might just need to clean the sensor cover on the grill.

 

Could I get some help with this? I've bought this code reader, updated the firm ware and paired the app with the device and it is still telling me there are no codes or errors even though my dash has the pre collision system malfunction message and light lit up.

 

The pre collision system malfunction could be a few different things. The scan tool I recommended was to reset zero point calibration. That won't help you if you have a sensor issue, bad calibrated sensor or some wiring damage. What caused the light to come on?

 

So I noticed that the light for the pre collision system would come on and the display would say the sensor needs to be cleaned when I was 4 wheelin. It would always go away after restarting the car, washing it or sometimes on its own. Then last week I was 4 wheeling in some heavy rain and it came on but this time said pre collision system malfunction and has not gone away. Two things are at the top of my list as possible causes. First is that the truck was modified before owning it, so it has a lift and aftermarket brush guard and grill. The grill doesn’t have a cover for the sensor and I noticed that the sensor was moved and just zip-tied to the grill. I’m guessing the metal from the brush guard and lift were causing problems with the sensor and is why it was moved. Second I did notice that the wiring was exposed near the connector to the radar sensor. I’m not loving that and would really like to replace that either way but unsure of how to go about that. Is there a semi cheap scanner that can read those codes to find out exactly that is wrong, or should I bite the bullet and take her to the dealership who’ll probably tell me that it’s been modified and there’s nothing they can do?

 

Does the brush guard obstruct the sensor at all? The sensors don't like anything even close to in front of it. Has to have a clear sight of view.

The sensor being zip tied and the wiring being exposed are going to be your issues. Can't just have the sensor zip tied there. I would be looking for a used takeoff grill, with sensor preferably. Maybe on ebay or a junkyard. Can check car-part.com as well.

For the wiring I'd be looking for a new or used pigtail to splice in. Taking this to the dealer is going to cost a fortune. With a new/used sensor it might require calibration with specialty tools and targets.

 

Regarding the scanner, did you get into the ABS menu when checking with the Innova scanner?

A more sophisticated scanner that can read that sensor code would cost several hundred if not thousands. Unless there is a reliable one out there that I'm not aware of.

 

Back story (I have Techstream and the Tactrix cable so I am good on the scanner side) - I replaced my steering wheel and had issues with all sorts of warning lights. I apparently f'd up the steering wheel sensor somehow (it's attached to the clock spring). I tried an aftermarket sensor. It cleared all of the warnings related to the steering angle but it would never initialize. I even talked to the service mgr at the local Toyota dealer. He printed out the same info I got from the TIS database on how to clear and initialize the steering angle sensor. He said I was doing it correctly so we figured it was the aftermarket sensor. I caved and bought an OEM one and it solved all of my code issues. I am still getting the Pre-Collision malfunction but Techstream can't find any codes. I've read about codes being stored so they don't show up as a code in either the current or history category. TIS has a 2 day subscription (Techinfo.Toyota.com) that has all of the data the dealers have access to. I used that at the beginning of this whole mess. I'm going to get another 2-day subscription to see if there is a solution to this before messing with the actual sensor.