A 2007 annual production FAW - Volkswagen Magotan 1.8TSI sedan, mileage of 10,000 km, the user called the vehicle can not be normal driving request for rescue. After the rescue personnel to the car back to the maintenance station, the maintenance staff to test the vehicle, when the car engine in the idle run when the jitter was particularly powerful (similar to the lack of cylinder), but in the cold high speed or engine speed of more than 1500r / min When the symptoms are not obvious. After the maintenance staff and asked the user about the car on the situation, the user reflects the car has been used normally, but in the red light will be some jitter.
    Maintenance personnel first connected to the fault diagnosis instrument VAS5051 to detect the vehicle, the device prompts the engine control unit, ABS control unit are stored in the fault code. The fault code stored in the engine control unit is "Camshaft position sensor, engine speed sensor arrangement error", and the fault code stored in the ABS control unit means "Please check the engine control unit fault memory". Afterwards, the service personnel used the special tool VAG1763 to check the cylinder pressure of the spark plug and the engine cylinder. The inspection results showed no abnormality in the spark plug. Maintenance of the manual specified by the engine cylinder pressure value of 1.1 ~ 1.4MPa, so the cylinder pressure test results are clearly not normal. What is the reason for the cylinder pressure is too high? As the car carrying the engine for the turbocharged cylinder direct injection engine, maintenance personnel suspected of the cause of the failure may be the engine combustion chamber carbon or turbocharging system abnormalities. So they first on the car engine for carbon deposition work, but the cleaning work is completed, the test failure still exists. Then they checked the turbocharging system. They found that if you unplug the air flow meter plug, disconnect the turbocharger, test failure symptoms improved significantly, but the engine idling conditions are still not normal, the fault diagnosis instrument also shows the meaning of "camshaft position sensor, engine speed sensor layout Error "of the fault code. They also found that if the control engine speed exceeds 2000r / min, the fault code can be cleared. After the above checks, they determined that the failure was not in the turbocharging system. Troubleshooting is in trouble.