The automatic air conditioner of Passat V6 2.8, sometimes it is not cool, the pump does not suck. When it is not cool, enter the air conditioning system to check the data flow, 08-08-001, the first data is 8.0, and it is the outdoor air sensor G17. Looking at the outdoor air at this time, the displayed data is 42.5 degrees, and it will drop to 38.0 degrees when the vehicle is driven. Strange thing, there is an outdoor temperature. . . .
When I was in trouble, I removed the air conditioner panel, pulled out all the plugs, measured the plug, and looked at the circuit diagram. I couldn't find which terminal the outdoor temperature sensor went into the air conditioner computer, so I plugged it back into the air conditioner panel to check again, and found that the outdoor temperature of the instrument and the air conditioner panel both showed -8 degrees Celsius. Find the outside temperature sensor, replace it, problem solved.
Experience: The data stream seen by Passat's outdoor temperature sensor is not necessarily real-time. Unplug the plug to discharge and then plug it back in to see the updated data.
The refrigerant in the air conditioning system has leaked out, resulting in no refrigerant, so the air conditioner is not cooling.
You can check whether some parts in the air conditioning system, such as pipelines, air conditioning pumps, condensers, and evaporators, are damaged and cause refrigerant leakage. There is also an inspection method that can add fluorescent agent while adding refrigerant. After the vehicle has been used for a week, use a special fluorescent lamp to check the air conditioning system. If there is a leak point that will light up, it means that this part is damaged.
2. The interior of the air conditioner pump is damaged, resulting in the inability to start the cooling effect. Generally, abnormal noise will appear when the air conditioner pump is damaged. So check the air conditioner pump, if it is damaged it needs to be replaced.
3. The radiator fins of the condenser in the air conditioning system are too dirty, resulting in excessive pressure and temperature of the air conditioning system. In order to protect the air conditioning system, the air conditioning pump stops working, so the air conditioner does not cool. You can use a high-pressure water gun to clean the cooling fins of the lower condenser. Blow dry with a high-pressure air gun after cleaning.
The above is the common method of checking and judging the fault points of the air conditioner not cooling.
A 2003 Volkswagen Passat 1.8T sedan with a mileage of over 300,000 km and a 01V automatic transmission. The car is not cooling when the air conditioner is cooling, and it is sent to the factory for maintenance.
Fault diagnosis: First, let’s briefly talk about the car’s air-conditioning system. It is equipped with an automatic air conditioner with magnetic suction variable displacement (50% and 100% displacement). There is a hydraulic pressure automatic adjustment valve inside the lower part of the compressor (see the installation position). Observe that when the car's air conditioner is not cooling, the magnetic attraction is also attracted, but the pressure is 850kPa, that is, the compressor is not compressed. Since sometimes it cools normally, it means that there is no problem with the refrigerant in the system, and the compressor can sometimes cool normally, which means that the compressor compression system is also okay. After many test runs, I found a strange phenomenon, that is, when the air conditioner is just turned on, it is cooling basically every time. After about 20 seconds, the air conditioner will not cool down, and sometimes it can work normally for several hours. The cause of the failure is determined to be the failure of the variable displacement hydraulic white dynamic control valve (some reason causes the control valve to fully open) or the throttle valve failure (too large opening). So the throttle valve was disassembled (the function is equivalent to the expansion valve of other cars, and it can also be said to be a kind of expansion valve). The throttle valve is outside the evaporation tank, and the right front high-pressure joint of the engine compartment is on the side of the firewall (as shown in Figure 1). There is no problem on the surface of the variable discharge valve, but I don’t know if there will be a problem inside. There is a pressure regulating device inside. When the pressure reaches a certain value, it will open the hole of the "pressure relief" function to allow the excess refrigerant to flow back into the uncompressed low-pressure chamber. This is the function of pressure regulation. Try to make the magnetic suction less on/off to protect the engine. Since it is impossible to actually detect whether the throttle valve opens too much under a certain pressure, or the displacement regulating valve is straight through (caused by the fatigue of the spring inside), it is decided to replace the two together and perform a comprehensive cleaning of the compression cycle system. [
After replacement, refill refrigerant oil and refrigerant according to regulations.
The installation position of the throttle valve is shown in Figure 1. When installing, there is a hole about the same size as the position where the variable discharge valve is installed on the compressor. The corresponding hole of the compressor should be staggered from the hole of the variable discharge valve. It is not suitable for hole-to-hole installation. The farther the two holes are, the better. In addition, the throttle valve and displacement regulating valve should be soaked with refrigerant oil before installation. Firstly, the sealing performance will be better, and secondly, the throttle valve and displacement regulating valve will be prevented from premature wear or function damage due to lack of proper lubrication.
Troubleshooting: After replacing the throttle valve and displacement regulating valve, add refrigerant according to the regulations, and the cooling is normal, and there is no longer the phenomenon of sometimes not cooling when cooling.
Fault summary: In fact, it is relatively simple to solve this fault after knowing the cause. For such an old car, the cost of replacing the entire compressor will be relatively high, and some car owners may not be able to afford it. So I chose Xiu to solve the problem. While solving the problem for customers, I also advertised in another way.