Speedometer jumps
Thread Starter
|
Cross-Country
Joined: Sep 2018
Posts: 64
Likes: 1
Speedometer jumps
I have 2008 F250 5.4L automatic supercab. I have an issue with a couple things. The speedometer will jump around when the vehicle is not moving. Sometimes it happens immediately when I turn on the key and sometimes it will jump once when I start the engine. Generally when it jumps around a lot after just turning the key on the red brake light will also stay on along with the ABS light. I have done a lot of pinpoint checks and found nothing wrong so far. One thing I did notice was that if I disconnect one front ABS sensor, it can be either side, the speedometer does not move when starting or just turning on the key. I do not know why the front sensors have any impact on the speedometer since the VSS on the rear diff is the speed input. I have done a test rotating the front wheels to prove out the front ABS sensors and they are fine. I have checked voltage to the sensors and it is fine. Anyone out there with any thoughts on this?? The speedometer seems to operate fine when I start driving.
I have the Mitchel wiring diagram and I see the Yellow Blue wire going from the ABS VSS pin to the PCM VSS pin. There is a splice (S130) that shows a takeoff to the 4x4 module and to the wiper motor. I have no idea why there would be any connection to the wiper motor. Is there anyone out there that can explain that one?
I have the Mitchel wiring diagram and I see the Yellow Blue wire going from the ABS VSS pin to the PCM VSS pin. There is a splice (S130) that shows a takeoff to the 4x4 module and to the wiper motor. I have no idea why there would be any connection to the wiper motor. Is there anyone out there that can explain that one?
Thread
Thread Starter
Forum
Replies
Last Post
low54
1987 - 1996 F150 & Larger F-Series Trucks
5
Jan 8, 2009 09:18 AM
tobyw
1987 - 1996 F150 & Larger F-Series Trucks
3
Aug 14, 2007 11:02 AM
