Failure phenomenon: a 2007 annual output of FAW – Volkswagen Magotan 1.8TSI car, mileage 68600 km. According to users to reflect, car engine fault lights often lit, this failure has also not ruled out several repairs.
Analysis check: Check the fault lamp lit, a warning light emission was found. After that communicate with users, exhaust emissions warning lamp post, if flameout after starting, then the warning light goes out, a long time will not light up, to serve also can not find fault codes when the station maintenance, but after some time the lamp will light up warning emissions. When the warning lamp, and no significant abnormalities engine performance, acceleration and driving performance are good.
Query car repair record, replaced when the steering lock cylinder over 30,000 km, and the system control unit comfort, up to now there has been a new car coolant level fault warning lamp, but no inspection result, 3 after ten thousand km added emissions warning lamp lit, and because this failure has replaced the intake manifold damper position / operation control sensors.
FIG 1
A failure diagnostic system checks VAS5052, store fault code P2015 (FIG. 1), meaning ldquo; an intake manifold flap location / operation control signal of the sensor is unreliable, sporadic rdquo ;. Considering the car replacement intake manifold damper position / operation control sensors, should match the engine control unit and the intake manifold of the flap (FIG. 2), thus guiding the use of fault diagnostic function, according to the fault diagnostic the prompts. Note that when operation, first ensure that the battery voltage is higher than 13.72 V, matching with the engine idling, matching the actual opening degree of the intake manifold flap will continue to become larger, final tips off the ignition switch 50 s wait matching automatically. After the matching operation, a read data stream engine 142 set in an idle condition, the intake manifold flap the actual position of 0.00%, the intake manifold flap 0.00% target position, the intake manifold flap voltage compensation value 3.82 V, 3 min after the above value becomes 0.80%, 0.00%, 3.82 V. When sudden acceleration, the intake manifold damper position / operation control of the sensor has been fully opened, the mechanical portionPieces of work, but to view the data stream, you can see the sensor value was 99.2%, which is not normal, this opening signal come from? Dismantling decided to check the intake manifold.
FIG. 2
Figure 3
Considering the intake manifold damper position / operation control sensor replacement time is not long, the likelihood of damage is very small, so a sensor for measuring the quiescent voltage supply, the result is a normal 5 V, the ground is normal, test gun vacuum intake manifold vacuum valve flap (FIG. 3 ) also found no signs of leakage. Further analysis, if the solenoid valve controlling the vacuum leak throttle position sensor, the position sensor will cause an incorrect signal, the engine control unit detects the voltage sensor incorrect fault lamp lights up, and also checked to exclude this possibility. Remove the intake manifold, the intake manifold flap is rotated while the data read intake manifold damper position / operation control of the sensor, as long as the minor found that the intake manifold tubes do radial movement flap, intake manifold the actual position value tube flap will have a greater change, which is not normal.
Figure 4
Troubleshooting: Loosen the intake manifold damper position / operation control sensors (FIG. 4) of the two fixing screws, through the fault diagnostic value of the actual position of the intake manifold flap, while carefully adjusting the position of the intake manifold damper position / operation control of the sensor. Until the intake manifold flap in the closed state, however radial movement, the reading sensor data stream no signal is output as the optimum position. It can be seen before and after installing the sensor position adjusting a difference of about 0.5 mm, the adjustment is completed after a long period of test, all normal data, emissions warning lamp is not lit again.
(Ma Ji)