What does a lean fuel system in the Passat mean?
2 Answers
Insufficient gasoline pressure, oxygen sensor failure, air flow meter failure, intake system leakage, fuel injector blockage. Related knowledge is as follows: How to deal with lean fuel fault: The occurrence of a lean fuel fault may be due to excessive air intake in the engine and insufficient fuel injection during operation. Check for any foreign objects blocking the air filter, determine if fuel quality issues are affecting the oxygen sensor, which could lead to reduced fuel injection by the engine, or if the fuel pump is blocked by foreign objects causing fuel pump pressure issues, resulting in a lean fuel system. If the vehicle exhibits a lean fuel fault, immediately go to a 4S shop or repair shop to identify the cause of the fault and carry out repairs.
Last time my Passat showed this fault code, it was actually because the engine wasn't getting enough fuel. The car's computer detected an incorrect air-fuel ratio - normally it should be 14.7 parts air to 1 part fuel for optimal performance. I've found three common trouble spots: First, a dirty mass air flow sensor giving false readings (can be fixed by spraying electronic cleaner); Second, fuel system issues - check if the fuel pump pressure is adequate and if injectors are clogged; Third, engine air leaks - a cracked PCV hose can let unmetered air in. Once I found a hidden leak: the oil cap gasket had aged and wasn't sealing properly, fixed by replacing it for just 20 yuan. Don't ignore this fault - otherwise the exhaust pipe will glow red and fuel consumption may double.
