Flashing VSC and slip indicator on...

I was driving home on the highway about a week ago and the VSC On light starting flashing and the slip indicator lamp below it was on. I never seen this happen before.

After a quick stop, I was back on the road. This time the same two lights came on plus the ABS light too.

After my final stop, I got back on the road. This time no lights were on. At least for the 5 miles I drove.


Fast forward to today as I was out of town since the prior encounter. None of the lights came on for the 50 miles that I drove. I did plug in my OBD2 scanner though as apparently the OBD Fusion app can read VSC/ABS data. It showed that there were four confirmed codes. The codes are C1223, U0123, U0124 and U0126. I also displayed all four speed sensors and the FR was reading about 15 mph lower than the other three wheels. I also tried to log and graph the data from all four sensors while driving.

With those codes, could it be a speed sensor?

Appreciate the help as usual.

See attached images.

 

What year is your truck and do you have the hydraulic brake booster or vacuum brake booster?

 

That’s it…….
I quit……….

 

2008 V6. I assume hydraulic. How can I double check?

Lol. I have to keep you guys busy.

 

See the link below
https://www.tacomaworld.com/threads/anyway-around-reprogramming-an-abs-unit.814675/#post-29217783

 

Definitely hydraulic.

 

The only things I see that all those modules have in common are the IG power circuit, the Ground at Ground Point IE, and the CAN lines.
I don't see the connection of the Left Front Speed Sensor though, I would expect that to generate it's own code.

Do those same codes come back as soon as you clear them?

 

Probably a dumb question, but will clearing the codes with my limited OBD2 scanner remove these ABS/VSC codes even though there is no check engine light on?

 

Did you recently lift your truck? Might need to reset the VSC

 

If you can read the codes and data from thw ABS I don't see why it wouldn't be able to clear them.

 

No, it's all stock. I haven't even worked on the truck recently. Just happened out of the blue.

I will try and clear them today. Not sure if that's OBD Fusion wording but what does "Confirmed" mean? If that means current, wouldn't the lights be on at the moment? Maybe I shouldn't compare how to the MIL or Check Engine Light works as compared to the ABS/VSC system.

 

On your particular tool I couldn't tell you but typically on every other module except engine/transmission you have 2 code lists, current/active (meaning the fault has been detected this key cycle) and history/stored (meaning the fault has been detected at least once in the past x number of key cycles (varies by vehicle and code how many good trips it takes to clear from memory) but is not present at the moment).

 

A bit more information here.

I found an historical code when I connect to what OBD Fusion calls the Generic OBD2 module. This is where I would normally go to get MIL engine codes. I have to say that I am not too familiar with checking codes on this truck as I never encountered one in the 100k miles that I have owned it with the exception of an evap code that I caused when I replaced my fuel sending relay earlier this year.

This historical code that I found was P0504. Maybe the brake switch is the root cause of the issue on VSC/ABS side? Clearly the issue is intermittent as there are no lights on currently.

I ended up clearing the 4 codes on the ABS/VTRAC module. I did not clear the historical code on the generic module since it is clearly noted as historical.

Anyway, I just wanted to provide an update here. I don’t really think it is warranted to keep investigating this issue unless this starts happening more.

 

Some more info here. For the most part the lights have been off but every now and again they would come on. I ordered an aftermarket sensor for the right side just to see if the slower speed issue reported by the front right sensor would go away with another sensor.

I installed that sensor tonight but it seems like the issue is still there. I have not driven it, but since the truck is on a lift and off the ground, I was able to spin the wheels to see what is being reported. What is really strange is that the new sensor does not report anything back when I spin the wheel. However, if I spin the front left wheel it reports back speeds for both the front left and front right sensor. Keep in mind that the front right wheel is not spinning. The speed being reported for the non spinning right wheel is also slower than the actual spinning front right. Similar to what I originally see when monitoring the speed sensors while driving.

There are no codes on now and there were no codes on prior to starting this experiment. Btw I did try and unplug the speed sensor on either of the front wheels and a corresponding code was set so I assume that the computer is aware of both sensors.

I didn't even want to post this as the behavior seems odd, almost like an internal electrical issue in the ABS module itself. I am going to leave everything as is tonight and drive it for a bit.

 

First guess is that two wires (one from FL and one from FR) are touching. Could be frayed insulation but more likely corrosion creating a bridge on the circuit board or a connector. We are dealing with a VERY low current AC signal from the sensor, so easily corrupted.