FL70, 3126, Engine Code "31"

[jcross]

I have a 1998 FL70, 3126 that keeps giving me from time to time a "31" code. According to the engine Operation and Maintenance Manual its the code for "Loss of Vehicle Speed Signal" does anyone have any ideas about this?

Problems, symptoms, location of sensor and what to do about it?

Yesterday I was on a long grade and the check engine light came on and I lost power for a few seconds and then it went back to running right.

Thanks in advance.....

 

[davekc]

That year 3126 engine has two speed sensors. You have a failure at one of them due to faulty wiring or a bad sensor. Typically when they replace one, they will recommend the other. If the other goes out, (failure at both) the engine will no longer run. I would advise geting that fixed before you get a problem you don't want.

 

[jcross]

Thanks davekc.

Are the sensors something I can do or does a dealer need to do it? If so, approximately what is the cost?

Thanks.

 

[davekc]

Not real expensive. I would go to a Cat dealer. They will be cheaper than a FLT dealer. I am thinking two to three hundred depending on the problem.

 

[jcross]

I just called the Freightliner dealer and the price for both of them is $120. They deliver to me and have been reasonable on prices (or seem to be).

I would take it in to CAT but all of the dealers are a good ways from me.

The wiring harness looks in fair shape. The truck has a remanufactured engine in it and I'm slowly as I can afford to fix/replace the things that go wrong.