TT011401

Tech Tips
Date: January 24, 2014
TT 01-14-01
2008-2014 Tiguan, Passat, CC, Jetta, Golf, EOS – DTCS P0171,
P119A Lean Fuel Trim Readings
Install a vacuum gauge on the dipstick tube and check crankcase vacuum at idle. Compare to a known
good vehicle. If the vacuum reading is lower than the comparison vehicle, visually inspect for oil leaks
between the engine and the transmission. Smoke test the crankcase by connecting the EVAP smoke
machine to the dipstick tube and inspect for leaks at the rear main seal (this will limit pressure to 2 PSI).
DO NOT apply shop air to the dipstick tube or the crankcase. If a rear main seal leak is identified, replace
the seal.
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