Random Throttle Input?

[FawnaFox]

Hello, I have a 1998 Freightliner FS-65 with a 5.9 Cummins and the electronic throttle. Randomly the engine will redline for no reason. The throttle is not being pressed and when you press it, the engine is under control, until you let off. The only way I found to stop is is to restart the bus. I have only had it happen once to this extreme, it will randomly surge a bit. Only after 25-30 minutes of idle (I was charging the batteries after jump starting) Does anyone know why this happens? I'd like to know.

 

[Mr P]

I've worked on pickups with that engine, but never seen your complaint. Check for engine codes. Check the TPS for accuracy with a scanner. The computer is either getting an erroneous TPS signal or the computer is losing it's mind. When the computer begins losing it's mind, sometimes it generates a p0600 series code (maybe 603?). Again, that's pickup truck code.

 

[SkyMaster]

The computer is either getting an erroneous TPS signal or the computer is losing it's mind.

^^^ This. When PCM's get age on them capacitors can fail and solder joints can crack, maybe keep an eye out for a used unit.

 

[Mr P]

If the engine data can be scanned when the problem occurs, the TPS can be proven to be good or bad. TPS is simple, cheap, and easy...compared to the ECM.