This will heat your bed up. Stay near your printer in case of problems.

Be sure nothing is on your bed.

Run this command:

M303 H0 S60

Your bed will go through a PID tuning cycle. When it's done, run M307 H0 to see the values, it will report something like this:

Heater 0: heating rate 0.427, cooling rate 0.344, dead time 6.25, max PWM 1.00, mode PID Predicted max temperature rise 117°C PID parameters: heating P66.9 I1.494 D292.5, steady P66.9 I3.509 D292.5

Using that as an example, find the M307 H0 line in your config.g and adjust it as follows, using the values for gain, time constant, dead time, and voltage from your M307 output.

M307 H0 R0.427 K0.344:0.000 D6.25 E1.35 S1.00 B0