Why is the cost -effective Villax with high cost performance?

Hello, everyone! Today I want to introduce to you a high -end SUV model owned by Hyundai Motor Corporation of Korea -Verax. Veraque design is fashionable, fine in interior, abundant space, low fuel consumption, and good power performance. Compared with the BMW X5 model, it is much cheaper, and the price and outlets of Veraque’s maintenance and maintenance are also very advantageous. For some friends who like large SUVs and have high performance and quality but do not want to spend too much money, importing modern Villax is a recommended model. But this problem is that the problem of minority is the place where the problem has always been sick. What’s wrong with this car? Take a look together.

[Vehicle Information]: A Modern Villax SUV off-road vehicle imported in South Korea in 2007, equipped with 3.8L gasoline engine and Japanese Aisin manufacturer model TF-81SC (modern model: F21-450) Fast/automatic integrated four -wheel drive transmission.

[Failure phenomenon]: The owner informed: About 300km driving on the road obviously feels that the transmission and engine noise are relatively large. At the same time, the speed of the engine is different from the actual speed. Come on in the snowy days). Therefore, the wheels are unavoidable, so the problem is more serious after continuing to move forward for hundreds of kilometers: the engine fault indicator has been lit, and the transmission is no longer automatically changed.

(F21-450 transmission appearance map)

[Fault detection and maintenance]: After receiving the car, conduct a road test, and find that the automatic transmission of the cold car is basically normal. After the hot car, it is also possible to step on the accelerated pedal, but you cannot step on the accelerated pedal to accelerate. Over large, the transmission enters the fault protection mode -lock file (fixed 3 gear). However, under the user’s advice, the transmission was disintegrated. After decomposing the transmission, it was found that the clutch C1, 4/5/6 -level clutch C2 and the 3/5/R gear clutch C3 of the clutch clutch were found. Essence Next, start looking for the accessories of the transmission.

After many folds, you can find the automatic transmission assembly of other models of the same model, and you can only remove the required components from the inside. Replace the relevant components (actually several sets of clutch friction pieces) and use its specified ATF rear loading car for road test. As a result, the new fault phenomenon showed that the trial of the cold car was basically normal, but the hot car appeared after the hot car: ① Human power file (R, D) delay and impact; Impressions; ④ 4-5 slide do not impact; ⑤5-4 and 3-2 shocks. Think of Lenovo’s usually occasionally impact phenomenon when repairing other new models. The electronic control system needs to initialize the matching and self -learning control functions, otherwise it is difficult to change and eliminate the irrelevantness brought by the shift. So carefully drive the car to the professional maintenance station, and use its special ECU to perform the learning function (multi -function switch and ECU integration) of the “various data removal energy” and “n” positions, and learn from a “N” position to learn a “N” location to learn from the position of the “N” position. Previously, the adjustment of the “N” position must be based on its adjustment requirements. After doing these jobs, there are TCM learning functions strictly in accordance with its control requirements. When replacing or repaired AT or replacing TCM, you need to re -study. When the requirements are required, you can only be executed in the D position.

In checking the above learning steps, the learning results of the N-D position are basically normal, but occasionally there is a sense of impact; the reverse gear is still jointly connected with a delay and is accompanied by a serious impact and has not improved. At the same time, the failure of the fault after performing a dozen shifts has changed significantly. Only 2-3 gears are slippery and impact and 4-5-gear slip: 5-4 and 3-2 shocks.

By analyzing these points and combining the transmission shift to perform the element worksheet, it is not difficult to find the problem that there is a commonality and concentrated on one point, that is, the most suspected component C3 that controls the 3/5/r. Connect the oil pressure gauge on the C3 measuring hole. During the test, the oil pressure was slightly slower when the pouring gear was found. At the same time, when the 2-3 and 4-5 gear, the oil pressure table had fluctuated up and down. Is there a leakage of the control instruction problem or the component execution work? So, the hydraulic valve body is cleaned again without disintegration transmission, especially C control the oil circuit inspection.

(C3 clutch measuring hole position)


After no problem of the hydraulic valve body and oil road, the road test was conducted again according to the original learning process. After a period of test, the problem had obvious changes. , Only delayed and impacted the R gear, and at the same time, the 2-3 gear slipped and impacted and the 4-5 gear slipped. It seems that the problem is concentrated on the C3 clutch. Is there a problem with the SLC3 solenoid valve that leaked or control C3? Because everyone believes that the probability of problems occur during assembly mechanical components is low, so start with simple starting, the C3 control valve control the front end of the SLC3 solenoid valve control the front end of the SLC3 solenoid valve Debug.

(The SLC3 solenoid valve on the valve body and the control valve of the adjustment screws)

After debugging the solenoid valve, there seems to be no change in the situation. Then I calmly think about why the cold car feels basically normal for the first time, and the above problems occur after the hot car. In this case, in this case, once again, the transmission is decomposed again, focusing on finding the C3 itself and controlling the oil circuit to eliminate the problems of the mechanical and hydraulic part. Decomposition the transmission, re -check all components and test work performance, and find the oil pores of each component to use the pressurizer for pressure tests. As a result, no problems were found. At the same time, the SLC3 solenoid valve was restored to the original position.


[Failure exclusion]: Although the mechanical part of the disassembly is not found, there is no need to have any doubts on the machinery. After loading, the phenomenon must be the same as the original, because the reason for a while, and it is not possible to blindly check any parts. Is it because the learning operation function has not been activated? So I simply conducted a road test for the forward gear for a long time. As a result, I felt that the shift was obviously better and better. Later, when the use requirements were almost met, the parking phenomenon was restored again. Hanging up? Later, I did n’t go to the backstrus again to learn the front gear again. As a result, the car was put on the back of the car again after the car was put on, and it felt very good again. In this way, it has achieved the requirements of the use of two days of forward and backstrus, but Occasionally, there will be a slight impact on the side gear, until now it will return to normal. But also left a deep thinking, that is, why the car’s study time is so long, of course, there may be some shortcomings in some parts that lead to a longer learning time.


Okay, let’s talk about this today. I hope the article of the master will help you! Let’s see you next time!


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