The PSOM only works with the tire sizes that are mounted on the rear axle. The 4 wheel ABS is unrelated to the PSOM in the 1995 E-series

The PSOM's Conversion Constant can only be reprogrammed six times. It is reprogrammed for tire size changes only and each time you reprogram the PSOM Conversion Constant the count is reduced by one.

If the PSOM is from a salvage yards cluster it may or may not have the right Conversion Constant in it.

Note that the rear anti-lock module can go bad and disrupt the signal from the VSS to the PSOM as it uses the same VSS generated information and is wired in parallel with the PSOM.