Based upon the 2000 Factory supplement which should cover your 2004, that code display for the ABS does indeed look like 6-1 which is fail safe relay B+ voltage. The diagnostics are cryptic. Clear the code and see if it comes back. If it does you need to check the charging system voltage and probably the +12v supply to the ABS unit in case the problem is wiring.
42 is the rear primary (bank 1 sensor 1) O2 sensor heater circuit problem. Could be a short or open circuit in the heater circuit. A short might be the cause of voltage problems for the ABS