The value returned by the OBDII pid for manifold pressure (0x0B) has a conversion error. It appears it is converted from decimal to hex twice.
eg manifold pressure 36 kPa. Command = 0x01 0x0B Reply = 0x41 0x0B 0x16 Returned value = 22 kPa. Multiplying by 1.6 will give something close to the correct value. 22 x 1.6 = 35.2 kPa. But some precision is lost.