Land Rover Repair: speedometer sporadic, vehicle speed sensor, throttle position sensor

Question
Yeah thanks John, I remembered to put the make and model after I sent the message.  I have a 96 Landrover Discovery SE7.  Thanks for the quick response.
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Followup To

Question -
Hi John, my speedometer is acting strange.  At any speed it will jump up 50 or so extra kms or sometimes it won't even work, it will fluctuate all over the place.  Any suggestions

Answer -
Hi Randy,

sounds like vehicle speed sensor (VSS) or wiring is at fault.  Could also be throttle position sensor (TPS) Depends on model and year.  Newer Disco's have sensors associated with ABS giving wheel speed...

Randy, next time please give model and year of vehicle.  It could make a difference in the answer you are given.

Best of luck,

JohnMc

Answer
Hi Randy,

VSS is located on Transfer Gearbox just behind tranny.  VSS feeds signal to ECU which in turn signals speedometer.  It could be the wiring from the ECU to the dashboard.

IF this problem is random, your work is more difficult.  IF not, it would be easy to determine if VSS is at fault:  just swap in a temporary VSS to see if problem disappears.

Best of luck,

JohnMc