2018 Taco TRD Off-Road Aftermarket Tail lights triggering errors (1 Viewer)

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Joined
May 11, 2023
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Location
Everett, WA
Hi, all! I've been trying to research this issue for months and I've run into nothing but dead ends. A bud of mine recommended these forums so here goes:

I have a 2018 Tacoma TRD Off Road with Pre-collision System (PCS). My 2017 Tacoma TRD (without PCS) was totaled last year. I was running these on the 2017 without issue. I pulled them off of the 2017 and put them on my 2018, and the errors began to fly once the headlights/tail lights were turned on (photos and video link below). To rule out any kind of electrical jostling as a result of the accident I bought this set. Same issue.

The truck would run fine until sundown/low beam headlights and tail lights were engaged. Once engaged, the truck would lose acceleration power (pedal to the floor and nothing would happen until completely depressed, then it would reset and acceleration became possible again). An ABS and PCS error would flash as well. Occassionally, the truck would be thrown into limp mode as well which was bizarre.

1. Has anyone else experienced this?
2. Is this a known issue with later model Tacos with PCS?
3. Has anyone found a work around or after market LED tail light that is actually compatible with a 2018 Taco with PCS?

Video link (it's a temp link, sorry guys): iCloud - https://share.icloud.com/photos/08e-Vnrirum3vFGtMRHS2YarQ

Taco1.jpg


Taco2.jpg


Taco3.jpg


Taco4.jpg
 
I took a quick look into the factory manual and don't see where the truck monitors the rear tail lights at all. It does monitor the stop circuit.

I assume those are LED lights (didn't pay attention). I have had quite a number of LED's back feed. I would look towards the tail light back feeding the stop circuit.

Pull the lens, measure voltage on the stop light wire with headlights on (make sure you have a good ground). "IF" its back feeding, remove the stop wire from both the lights and see if the problem goes away.

If it does, add in a diode. What's dumb is these are LED's, their not suppose to back feed.
 
I took a quick look into the factory manual and don't see where the truck monitors the rear tail lights at all. It does monitor the stop circuit.

I assume those are LED lights (didn't pay attention). I have had quite a number of LED's back feed. I would look towards the tail light back feeding the stop circuit.

Pull the lens, measure voltage on the stop light wire with headlights on (make sure you have a good ground). "IF" its back feeding, remove the stop wire from both the lights and see if the problem goes away.

If it does, add in a diode. What's dumb is these are LED's, their not suppose to back feed.
Thanks for taking time out of your day to look into this!! Gives me a great starting point for troubleshooting.
 
I was going to post the diagram but its a PDF and I cant convert it.
 

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