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[YesAuto Car Collection] since the last time the editorial department of the elders N hand BMW E46 318i evaporation tank clean, the elders of my love admiration as the surging river …… (500 words omitted here). A few days ago, it rained frequently in Beijing. After the heavy rain, the elder found that the interior panel near his E46 skylight was always wet, so he came to me again: “Lao Du, what's wrong with this skylight? It's not a leak, right? When checking for water leaks, the skylights were collapsed easily, and sometimes the switch card would be cured!


   I went and brought this one. Anyway, one child is also brought, and two children are also raised. The sunroof of this car has not been repaired. My colleagues dare not touch the sunroof button when driving this car. It can't be closed, I will try to make it clean once, and I will save it… (500 words omitted here), recalling the appearance of the elders at that time, it is still fresh in my memory.

Solve sunroof stuck

This E46 sunroof is notoriously defective. Sometimes it can’t be opened at all, sometimes it gets stuck when it is opened halfway, and sometimes it stops when it is closed halfway. Every time such a phenomenon occurs, it is accompanied by a “crack” sound, and it feels like the skylight is stuck with something. Many colleagues got recruited when they drove this car. They called us and asked what to do. It's really time to fix it.


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More exciting videos, all in the car home video channel

This is a typical case of minor failures that are not repaired and slowly lead to a major failure. Although it did not cause damage to the sunroof assembly, it is necessary to summarize the lessons. Now the sunroof control technology is relatively mature and will not be easily damaged. The sunroof is designed with self-protection function. Once the output torque signal of the DC motor exceeds the set authority value, the sunroof control module judges that the sunroof is clamped or mechanically stuck. It will cut off the working current of the DC motor to achieve the purpose of self-protection.

Solve the sunroof collapse

The sunroof opens and closes normally, and the next step is to solve the problem of sunroof collapse. Some models will encounter the problem of sunroof collapse, mainly because they are unsightly. People with obsessive-compulsive disorder can hardly bear it. In fact, they can't feel anything when using it. Perhaps when many people think of the sunroof collapsed, they first think of manually adjusting the height. In fact, this is not right.

During the operation of the sunroof, there is a corresponding relationship between the working current of the DC motor and the mechanical resistance of the DC motor. The sunroof control module recognizes the operating limit position of the sunroof according to the working current signal of the DC motor. This identification process is called the standardized setting process of the sunroof. Restoring the initial setting of the sunroof is to allow the sunroof to relearn the limit position of the raising function.


More exciting videos, all in the car home video channel


More exciting videos, all in the car home video channel

The reason for the sunroof collapse is mostly caused by the change of the upper limit position of the sunroof stored by the control module. At this time, it can be solved by restoring the initial setting of the sunroof. Some manufacturers will write this method in the vehicle manual, and some will not. There is a lot of difference between the height of the sunroof and the roof of the elder E46. After the initial setting is completed, the height must be adjusted manually.

Solve the skylight leak

The rest is to solve the water leakage of the skylight. This problem is relatively common, but it cannot be understood literally. Sunroof leaking means that the drain hole of the sunroof is blocked, causing the water that should be discharged to the outside of the car in time to flow into the car through the gaps in the sunroof. Usually, no water droplets are seen in the car, only the damp roof, and the water is smooth. The A- pillars on both sides flow to the dashboard and finally to the floor inside the car. With the consent of the elders, I did the following demonstration.


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to sum up

Up to now, the three problems of the elder skylight have been solved for two and a half, and the remaining half will be fine if it is not repaired. Among the three failures, the skylight leakage is the most common and the most concealed. Under normal circumstances, the skylight leaks are not detected in time. Careful car owners will find water stains on the floor inside the car, but they don’t know where the water comes from. There is also a situation where the water in the floor soaks the electronic equipment in the floor and causes a malfunction. The car owner only discovers the problem and goes to the repair shop for repairs. It was only then that the malfunction was caused by a leak in the sunroof.

Although the opening method of the panoramic skylight is somewhat different from that of the ordinary skylight and the sealing method is also different, the drainage methods of the two skylights are the same, so there is no difference between the methods of cleaning the two skylight drains. Now that the sunroof product technology is mature, the probability of jamming and collapse is very low. As long as you pay attention to cleaning the roof in time, avoid debris falling into the sunroof when the sunroof is opened, and the phenomenon that the drainage hole of the sunroof is blocked will be greatly reduced.