Your advise is fine for the systems that it applies to after the onset of onboard diagnostics.
Unfortunately this one squeeked in under the wire. There are NO impulse diagnostics on ANY system untill 1988. ABS didn't get onboard diagnostics until 1992 and never appeared in 6cyl 124 cars (did appear on 124.034 and 036 in 1992)
Bosch Master, ASE Master, L1
33 years MB technician