Sensor Burnup Mystery

[chrisohle]

I recently purchased a second 2004 MINI Cooper R50 with two issues (not starting and not shifting into higher gears with a CVT). Using ISTA and INPA, I found that the transmission would throw an EP error once it had issue with the Rotational Speed Sensor (0721). I attempted to replace the original, same issue arose immediately. I replaced the connector...same issue. Thought it might be a bad sensor...replaced with no fix. Noticed the wire on the pigtail had burned up the insulation was completely gone, exposing bare wire on all three wires. I replaced the engine wire harness and another sensor...burned up again! No issue on the wire in the harness, just from the connector to the sensor. This is all that has been done so far, but it still losing sensors
- Replaced Engine Harness
- Replaced ECU (Computer) with a newly programmed device
- Replaced Engine Fuse Box
- Replaced TCM
- Replaced Valve Body

The car is started, moved no more than 100 yards, checked and the wire is already destroyed.

The picture shows the insulation that has been completely destroyed.

I'm stumped...Any ideas?

[Rush2252]

This is an old thread but the only thing that will cause a wire to burn insulation is a dead short to ground on a hot wire. I would take a meter and check resistance of the solenoids inside the transmission, did you pinch one of the wires inside when you replaced the valve body? If you pinched a hot wire then it’s grounded and will dead short as soon as power is applied.