need to calibrate a number of modules hosting on a M30 anesthesia monitor. Can I access through service mode on monitor, what is the service password?

The default service code is 1345.   

Yes. Do you have any of the Philips service manuals? Because the M3015A is referenced in several of the manuals, and the password is also mentioned. But a full PM does require some equipment. You need a low flow Thrope tube to verify 50 mL/min of flow into the module, 5% and 10% cal gas, and the appropriate tubings.

And the service password should be in the manuals. I can say it's a 4 digit password but I think they'll growl at me if I come right out and say it. :-)  

Ray Brown, CBET is right, instruments are needed for calibration. A password will not solve the problem.