(Text/Meiho pingming Li He)
Failure phenomenon
Audi A6L 2.0T sedan, equipped with BPJ engine and 01T transmission, mileage 188,790km. The car has insufficient power while driving.
Fault diagnosis and remove
Use diagnostic equipment 5054 to detect fault records such as fault code: 00665 (supercharging pressure control is lower than control limit value) in 01. Analyze possible reasons through fault guidance: 1. The boost pressure is lower than the specification; 2. Turbocharger air recirculation valve-N249 is faulty; 3. Leakage between turbocharger and intake manifold; 4. The hose connection of the supercharged pressure control solenoid valve-N75 is faulty; 5. Supercharged pressure control solenoid valve-N75 is faulty; 6. The supercharged pressure in the turbocharger controls the air leakage of the air door; 7. Turbocharger is faulty; 8. Catalytic converter shut down. Through inspection and analysis, the two items with the highest failure rate in normal times were mainly checked: air recirculation valve of supercharger and catalytic converter. During the inspection, the three-way catalyst was found to be blocked (figure 3). Replace catalytic converter and troubleshoot.
Maintenance summary
At present, there are many reasons for insufficient power of A6L 2.0T engine in actual maintenance. Some photos of common faults in the workshop are provided here for your reference:
1.N249 diaphragm is damaged (Figure 4);
2. The three-way catalytic converter is blocked;
3. The inlet cooler pipe is blocked abnormally (figure 5);
4. The connection hose of N75 is broken;
5. The turbocharger leaks oil, causing a large amount of oil stored in the cooler to cause the intake to be blocked and unable to run;
6. High pressure pump Cam damage leads to insufficient pressure;
7. Timing deviation between two camshafts, etc.
