DTCS P0171, P119A Lean Fuel Trim Readings (CTT 01-15-01)

Publication date: 2015-04-28
Reference number: CTT 01-15-01

DTCS P0171, P119A LEAN FUEL TRIM READINGS

TECH TIPS - CANADA

Reference Number(s): CTT 01-15-01, Date of Issue: April 28, 2015

VOLKSWAGEN:	2008-2014 Tiguan, Passat, CC, Jetta, Golf, EOS
GROUP:	01 - On-Board Diagnostic (OBD)

SERVICE INFORMATION

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. Once replaced, recheck crankcase vacuum at idle. If low, check for additional oil leaks and verify crankcase breather operation (repairing as necessary). Erase the faults and road test 16 kms to recheck operation.