My 2001 TT is throwing a M.I.L Vaged it and got "Fuel Injection pump controller supply voltage low" cleared it but will always reappear after 2nd start. F.Y.I my battery went dead the other day and I haven't been able to charge it. The "no load" test it saying 12.2 volts. Has anyone had a problem like this and do you think it's linked to the weak battery?
More and more batteries are falling under the "non-serviceable" category. Meaning, you don't check the fluid level because they are sealed shut. If you do have a serviceable battery, there are plastic "caps" or "vents" on the top. Usually two long ones, but that varies on the battery size and such. Heres helpful link:
Read the warnings! And not all battery "screw" off like the one mentioned.