Volvo: 1995 Volvo 850 DTC Led Light, volvo 850, generic tool

Question
Hey Ray!
My 95 850 had the flashing arrow/Limp home mode issue intermittently. I replaced the gear position sensor, which didn't help. The RPM gauge also stopped working, so I replaced the RPM sensor on the Transmission. When I try to check the A-1 Diagnostics, the RED Led stays permanently lit, and won't respond. All other diagnostics work fine though, on A and B. I swapped out a TCM computer from another identical 850, but no change...could the ECM be at fault? Any ideas?
Thanks for your time!
Jason

Answer
Jason,
I doubt the TCM is at fault. There must be a fault in the diagnostic box. Are you sure that the gear position sensor is correctly set? I would try to read the codes using the Volvo scan tool, sometime that will communicate better than a generic tool or reading them manually.