Disconnecting the battery won't do anything.
I seem to remember these have a shared earth with something else that can affect the signal, try tracing the earth back and cleaning it up at its base. Failing that, you could test the wiring for continuity, and if thats ok try making a new, separate earth for the tps.
I seem to remember these have a shared earth with something else that can affect the signal, try tracing the earth back and cleaning it up at its base. Failing that, you could test the wiring for continuity, and if thats ok try making a new, separate earth for the tps.