I'm hoping someone will be able to help me with this problem. The
truck starts fine, but instrument panel completely dies and guages
zero out when I release the emergency brake. When emergency brake is
enguaged, guages work, but all MIL lights are always on. I ran scan
on truck and DTC code thrown ia P1687 which makes sense. I then
proceded to run EMIC test and it threw codes: 920,921,940,960,999.
These codes suggest that the PCM and TCM aren't sending information to
the EMIC. Just my guess. Sometimes odometer will read "NO BUS" after
the scan. Can anyone offer me any suggestions? I'd hate to start
replacing expensive control modules and the problem could be a simple
ignition switch. Any advice would be appreciated.