About 30(?) different test parameters/functions inside of Test Mode. Most functions have never been dis-ciphered and remain a mystery,- afaik. Only useful ones I know of/remember atm are Engine Temp & Battery/Charge voltage level. Only 2 but very useful at times. One of them is displayed as "fp" but readings are not what I hoped; fuel pressure.Just for grins, why would we want to be in "test" mode. What is the car testing while in this mode??