Sounds like you need to reload the machine constants.
When was the battery last changed? When the battery goes bad it dosn't have enough
power to keep the constants in memory.
Is your control a 432-9 or -10 ? The -9 controls have a switch in the electrics cabinet
to turn the constants disply on or off, sometimes that switch dosn't make contact the way it should and can give you the M60 error.
If you need to know more just ask.