Audi Repair: audi a6 code 1471, audi a6, afew days

Question
Greg    We have a 1999 a6 quattro avant with 102k miles, code # 1471 is up. I tuned it up and the light went out but then came back on afew days later, coincidence?
 Also, the trans slips when it is really cold, 3rd to 4th is worst, isnt there special fuid in this and is it difficult to change screen and fluid in trans. I am a mechanic and do this stuff on my other cars and trucks. Also have a couple other issues but these are most pressing.                  thank you         Jim

Answer
hello
P1471 - EVAP Emission Contr. LDP Circ.

Short to B+
LDP pump is used on Audis to check for any leak in fuel system. Pump is located at L/R wheel, behind the fender linning. It has 3-pin connector, you can check resistance on: ?٠Terminal 1 to terminal 3: 640-720 Ħ
?٠Terminal 2 to terminal 3: 11.0-21.0 Ħ
if it's out - sound like a bad pump. I'm not sure which pin on the connector , but there has to be power and ground, right?
Trans...
yes , there is a special Audi synthetic fluid. Drain and replace filter is not a problem , but to fill it - it is.
Trans has to be filled from the oil pan's big plug and it has to be at 30 to 32 deg. Celsius.
good luck                  pltech