Luddite13

Hey all,

Recently picked up a rather clean 2003 A6 2.7T 6spd. Nice car, dealer maintained all its life. PO said it has a stage one chip, but he couldn't tell me what brand... Anyway, ran great for 400 miles after I bought it, then started bucking and the ESP / CEL lights came on. Lost all boost (limp mode?) and ran poorly.

Did some digging here and all threads pointed to a bad MAF sensor. I have VCDS Ross-Tech and it reported:

18010 - Power Supply Voltage 30 P1602 - 35-10 Voltage too low, intermittent
16487 - Mass Airflow Sensor (G70) P1030 - 35-00 Signal too high
17964 - Charge Pressure Control P1556 - 35-00 Negative deviation
17551 - Load calculation cross check P1143 35 - 10 Upper limit exceeded - intermittent.

Did some research here and at Ross-Tech and it pointed to limp mode and a bad MAF. So I replaced it with the Hitachi unit, bought online at ECS. Also put in a new airbox gasket and air filter. Cleared the codes and:

Same problem, car idles like crap, never got it out of the garage. ESP light came back on (not CEL), and the:

16487 - Mass Airflow Sensor (G70) P1030 - 35-00 Signal too high

is back, no other codes (didn't drive it it so it didn't go into limp mode?)

Anyway, did some more searching here, and it seems there might be a vacuum leak somewhere. Before I go digging around looking for a leak, is there any particular weak area I should start in?

thanks,

jcman

Freezing temps? Check the crankcase vent valve, it seems to cause vacuum anomalies.