Freightliner Century 1999 I can't idle up......

If there is an issue with your parking brake switch it will not idle up.
Or if you forget to apply the parking brake it won’t idle up

 

^^^^ he is more than likely correct.

Just gonna add, if it has optimized idle option from factory. It has a mercury switch on the hood. It tells ecm that hood is closed for automatic start. Its 2 wire and you can jump it with a paperclip.

I just can imagine a 1999 with opt idle parts still on the truck. But it's possible.

 

You need to get a prolink and plug in and see what sensor isn't communicating. There are like 6 sensor idk. Last time I really work on opt idle was 2005. Trying to recall everything.

 

Does it have 1 speed sensor but two plug and 4 wires in sensor?

Try switching plugs. Seem to recall this happening after someone would do a clutch job and mix up plugs.

 

Did the opti idle have a neutral safety switch on the old transmission - ?

 

I forgot about that one. Not at home. I cant pull out my dusty detroit bibles.

How you been Sir? Hope all is well.

 

Good, thank you! A little quiet lately and back on general freight to keep me busy.