VSC TRAC VSC OFF (4 Viewers)

[B1oodyBuzzard]

I’m troubleshooting the VSC lights on the dash and can’t get them to turn off.

I have had a few different codes intermittently triggering for O2 sensor and speed sensor but the only code I can’t clear is C1340 Center Diff Lock.

If I press the lock button on the dash I do not get the indicator the center diff is locked. I can hear the actuator working underneath.

I just replaced the position switch on the differential with no change and the old switch seem to test good continuity with a multimeter.

Hoping someone may have some insight. Please advise. Thanks

 

[badlander]

Have you tried moving the truck a little at slow speed? Sometimes it doesn't engage if the internal sliding parts aren't lined up.

 

[TahoeZ]

Speed sensor or speed sensor wiring can cause those other lights and the CDL code

 

[B1oodyBuzzard]

Have you tried moving the truck a little at slow speed? Sometimes it doesn't engage if the internal sliding parts aren't lined up.

Yes. Fwd and reverse. High and low.

 

[ceylonfj40nut]

I keep posting this but will do so here as well. I have 100 series where the same lights came on. Issue on mine was that the gas cap gasket was dry rotted and not holding a tight seal. Replaced it and all has been good for 3 years.

 

[B1oodyBuzzard]

I keep posting this but will do so here as well. I have 100 series where the same lights came on. Issue on mine was that the gas cap gasket was dry rotted and not holding a tight seal. Replaced it and all has been good for 3 years.

I don’t know if it was your thread or not I saw but my gas cap seems to seal okay. I can hear it release pressure some when I remove it for gassing up.

I’ve also been told that an exhaust leak or O2 sensor has caused the lights…. Not sure why those would have anything to do with stability control.

 

[ceylonfj40nut]

I don’t know if it was your thread or not I saw but my gas cap seems to seal okay. I can hear it release pressure some when I remove it for gassing up.

I’ve also been told that an exhaust leak or O2 sensor has caused the lights…. Not sure why those would have anything to do with stability control.

When someone stole my cats and cut my O2 sensors the lights did come on

 

[B1oodyBuzzard]

Just replace the Rear right speed sensor. No Joy.

Tried clearing codes again and the only one was the diff lock.

 

[TahoeZ]

If that's the only code you are getting and the actuator is working, most likely is the center diff lock sensor is bad.

Center Diff Light Fix - My Experience

Greetings. When I bought my '98 LX, the center diff lock light did not illuminate on the dash, when pressing the button or putting the transfer case into low. I'm posting this because in my searches to find a fix, I found a lot of good advice but it was kind of all over the place and there were...

forum.ih8mud.com

 

[B1oodyBuzzard]

If that's the only code you are getting and the actuator is working, most likely is the center diff lock sensor is bad.

Center Diff Light Fix - My Experience

Greetings. When I bought my '98 LX, the center diff lock light did not illuminate on the dash, when pressing the button or putting the transfer case into low. I'm posting this because in my searches to find a fix, I found a lot of good advice but it was kind of all over the place and there were...

forum.ih8mud.com

That was the first thing I replaced.

 

[TahoeZ]

That was the first thing I replaced.

Did you check/test the wiring?

 

[B1oodyBuzzard]

Just jumped in and started it. ABS and BRAKE lights came on in addition.

Could the ABS module itself be bad? What fuses or relay powers the diff lock.

I’ll have to dig in the service manuals later today