Medium and Heavy Trucks
Have Truck Repair Questions? Ask an Expert
Hi, my name is ***** ***** for your question.I'm reviewing your question now, and will post back with your reply ASAP.
When the engine looses speed signal it de-rates engine to 1500 RPM to keep guys from bypassing any speed limiter settings programmed into ecm
This does tell us it's a signal issue from the VSS (vehicle speed sensor) The sensor is located on back of transmission by driveshaft and can be replaced easily (replace VSS)
Just remove and install a new sensor,, screw new sensor in all the way then back off 1/2 turn and lock down nut
This should take care of check engine light and keep engine from not going above 1500 RPM
**********Please don’t forget to rate or accept the answer in a positive way, .**********EVEN IF YOU HAVE A SUBSCRIPTION ****THAT IS THE ONLY WAY I GET PAID **** You may still ask follow up questions at no extra charge after rating.Thank You
Make sure yoke on back of transmission is tight,, if loose it allows drive ring for speedometer to slip so sensor does not read correctly
The only other thing would be a wiring issue from VSS to engine computer (ECM)
It's a two wire harness he can follow from VSS to ECM and check for any rubbed out spots along frame, transmission, or engine or corrosion in plugs
Repair, clean, or replace as needed
If he wants to do a phone call I can send a offer for extra service just let me know if that would help?
Please use the star rating system at top of page so I get credit from the web site for my time,You may still ask follow up questions at no extra charge after rating.Thank you
Thank you for the positive rating very much appreciated.Please come back again you may ask for me if you like.Take care spanky