Brake Override Malfunction - Trac Off - Check Engine

Hi everyone,

I initially landed on this forum seeking help on the Brake Override Malfunction issue I’ve had on my 2016 Taco 3.5L with 54K miles for over 3 years and had yet to find a fix for it until last month. Many on here have commented on fuses, brake light bulbs/wiring, pedal commanders, oxygen sensors, disconnect battery etc… I even went as far as changing the throttle body. For the most part I had gotten used to driving it like that, it’ll go into limp mode, I’d pull to the side of the road, turn it off for about 1-2min and it’d go back to normal again and would probably happen again 2-3 more times, mainly on stop and go traffic. The dealer had no clue on what to do, mainly because it wouldn’t happen when I’d take it in and second, if it didn’t have a check engine light on they had no code to go by.

At times the Trac Off and Check Engine would be on simultaneously, but the only codes I got were Oxygen Sensor Bank 1 and Throttle Body. I replaced those and same issue, Check Engine and Trac Off lights back on and Brake Override Malfunction kept happening and going on limp mode often.

I watched video on someone having Trac Off and Check Engine on simultaneously and it was due to the knock sensor harness being chewed off by mice. Needless to say I took it apart and figured I’d change the knock sensors as well. Btw, my truck had no mice and the harness was intact. Anyhow, I replaced the wire harness and the two knock sensors thinking I was only (hopefully) fixing the Check Engine and Trac Off problem. However, changing the knock sensors and wire harness didn’t only fix the two lights I had on but it fixed the Brake Override Malfunction issue as well. The truck is running like new!

Sorry on the long write up, but this problem had me so frustrated, I felt it warranted a long explanation and clarity on all I did to hopefully help someone out that’s been having this issue .