ABS Engaged while driving no brake pedal

[03Lex470]

Hello all,

First post. I have an '03 Lexus LX470 with 265k on the clock. The wife was driving the carpool kids to school yesterday and while going approximately 50mph, the ABS engaged without warning and she was not pressing the brake pedal. She was able to pull over on the two lane road of Hwy 49 safely to let cars pass but it shook her up quite a bit. There were no warning lights on the instrument cluster before or after the incident occured. I had just bled the AHC system this past weekend but not getting any codes for it and she thinks it's me. I am getting the following codes C1223, C1224, C1241 for the ABS system. I'm hoping someone can point me in the right direction as to what to check first. I've been looking through the forums and can't find anything similar to what happened to my wife. Maybe I'm not choosing the correct search parameters.

The vehicle is bone stock except for LED bulb upgrades.

Thank you!!
-Greg

 

[leveeguy]

C1223 indicates a brake warning light output circuit failure in ABS system

C1224 indicates fault in engine revolution signal circuit specifically an open or short circuit

C1241 indicates problem with ABS system specifically low positive voltage to ABS module

 

[leveeguy]

https://forum.ih8mud.com/resources/2003-lx470-repair-manual-rm973u.194/download

 

[RapidRob]

C1223 indicates a brake warning light output circuit failure in ABS system

C1224 indicates fault in engine revolution signal circuit specifically an open or short circuit

C1241 indicates problem with ABS system specifically low positive voltage to ABS module

Judging by leveeguy's info it sounds like a power supply or more likely ground issue.

 

[03Lex470]

Thank you for the info. I really appreciate it.

-Greg

 

[03Lex470]

Wanted to give an update. After checking the battery and alternator for issues, I went an sprayed electronics cleaner on all the wiring harnesses, drove the vehicle around a bit then rechecked for codes. No more codes. Thanks again all who chimed in and for the LX470 Manual.

 

[J1000]

When it happened was she driving around a corner? When these trucks get old the steering rack bushings and other front end stuff starts to get worn out and the excess play can cause the stability system to come on when going around corners. Usually only when driving hard around a corner, but bumps can also trigger it. Stability system is basically the same as the ABS and usually triggers one of the front wheels to brake hard.

 

[03Lex470]

When it happened was she driving around a corner? When these trucks get old the steering rack bushings and other front end stuff starts to get worn out and the excess play can cause the stability system to come on when going around corners. Usually only when driving hard around a corner, but bumps can also trigger it. Stability system is basically the same as the ABS and usually triggers one of the front wheels to brake hard.

She said she was driving straight and was thankful she wasn't driving on the corners when the ABS engaged. It was really weird. No dash warning lights either.