Hello Everyone,
My uncle has a 2007 TCH.
The "Check VSC System" lights up while he is driving at normal speeds.
The following happens during a steady speed drive:
1. The "Check VSC System" and the skid light both light up.
2. The car seems to loose power.
3. The lights go away, and the car drives normally.
4. Then the whole cycle happens again.

All this happens every 2-5 minutes.

I would appreciate all your help.

Thanks

 

Take the car to someone with a pro level scanner and see what is going on. The ECU will have the codes stored for what is happening but from the sound of it, I think you have a wheel sensor going bad or a wiring issue.

The car is thinking that one or more wheels are sliding (like you would on ice) and is reducing power in an attempt to get the car out of the skid and under control. The yaw rate sensor or the control unit can also cause this to happen but more than likely, it is a wheel speed sensor.

 

If the computer is not saving any codes, then the failure must be similar to a normal occurrence, like a locked wheel. You would have to figure out how the wheel signals that, and that could be the cause. Short or ground in the wiring? Defective speed sensor? I would check the connection from the wiring to speed sensor on each wheel to see if it is tight. Remove and replace it to ensure there is a good connection. Also check for damages to the wiring.

 

Thank you for your reply GeorgiaHybrid and Ron AKA.
There are no codes stored. I checked using Toyota techstream.

I guess the smart thing to do is to check the wiring as you guys advised. If everything is alright, I will try to check the wheel speed sensors.

Any suggestions on how to test the wheel speed sensors?

 

I'm sure Toyota has a high tech way to test them. However, one low tech way may be to disconnect the pickup one wheel at a time and take it for a short drive to see what happens.

 

Good idea!
Thanks

 

Hookup your tech stream and set it to monitor the wheel sensors and go for a drive. Once the problem crops ups, hit the record data button and run it for a minute. When you get back home, take a look and see what is happening.

If the techstream can't do that, find a buddy with a Snap-on scanner, they will be able to help you out.

Did you check for pending codes?

 

I didn't check for pending codes...

I will hook it up on techstream and monitor the data...
Will update you with the results.

Thanks alot guys

 

One thing that might trigger that - uneven tires. If there is a notable size variance between tires (e.g. one or more being worn, or them being different sizes), you could get enough rotational difference to have the ECU suspect a skid.

The period between the spastic episode is what caused me to suspect that direction...

 

OTOH, the TCH comes with a space-saver spare and I presume this doesn't set off a VSC warning. My guess: it's probably a faulty wheel sensor.