Nowadays, more and more car models require decoding before lighting upgrades. Common ones include pulse detection, power detection, waveform detection, and multiple detection. Then the input signal from the driving computer is converted into digital form. Based on these principles, the current common decoding methods are as follows:
1. Capacitance decoding
The usual way is to use a capacitor to filter the trip computer's detection of the light bulb. The connection method is parallel connection (a capacitor is connected in parallel at both the positive and negative ends of the power cord). Depending on the size of the detection signal output by the trip computer, 22000UF and 4700UF are usually used.
This decoding method is for models with pulse detection and waveform detection, such as Mercedes-Benz, Buick, Chevrolet, etc.
Precautions:
1. The capacitor needs to distinguish the positive and negative poles, and cannot be connected reversely. Reverse connection will burn the capacitor.
2. Try to choose imported capacitors because domestic capacitors have serious false standards.
Decoding principle: Because the waveform value output by the trip computer is relatively short and can be absorbed by the capacitor, the current reaching the ballast is the direct dial current, thereby achieving decoding
2. Resistance decoding
The usual decoding method for calculating the car is Ohm's law R (resistance) = U (voltage) / I (current)
For example, after the car is started, the voltage is 14v, the current of the halogen bulb is 5A, and the required resistance is 2.8Ω. (Vehicle current reading can be done with a multimeter, just take the approximate value)
Advantages: high decoding rate
Disadvantages: The resistor itself generates a lot of heat, and there is a risk of burning the car.
3. Modify the CAN protocol of the driving computer
Mainly for Volkswagen, Skoda, Audi and other models, the decoding software used is 5053.
For conventional cars, you only need to install the VCDS software, find the vehicle OBD interface under the driver's seat, plug in the 5053, open the software, find the xenon mode in the 09 central electrical system of the software, tick it, and execute it (xenon for some models mode in 46, central comfort system). This decoding method is the most scientific (the new Sagitar will cause the daytime running lights to turn off after turning on the xenon mode)
BMW uses ESYS engineering software, NCS engineering software, Ruijin software, etc.
Fox decoding only requires 327 software, which can be used with the decoding software downloaded from the official website.
4. Decoding line group
Mainly for Korean cars, after installing imported ballast, due to the large starting current, the left and right light bulbs will flicker, so only a single light cord set is needed to solve the problem. In fact, normally speaking, these cars do not fall within the scope of decoding, such as Suoba, Langdong, etc.
5. Conventional decoding stabilizers and decoders
There are also the most commonly used ballasts and decoders with decoding. The principles are the same, decoding through EMC.
At present, there are more and more new models, and the CAN protocol is becoming more and more complex. First of all, when you get a car, you have to judge which method the car needs to use to detect the light bulb, and then decide which decoding method to use. For example: New Focus, 14 models of Compass, their driving computer judgment method is multiple judgment, it is difficult to use conventional decoding method alone. For models with multiple decoding, try to modify the driving computer decoding method, other methods may not be possible. pass.
Expand knowledge: Burn the driving computer
We often encounter that after installing XX models, the driving computer is burned out. The most common one is the Octavia high beam. The biggest culprit causing the original car's driving computer to be burned is interference.
According to the working principle of the ballast, there are two types of interference: 1. Radiated interference, 2. Conducted interference.
Radiation interference: The radiation generated by the ballast during the voltage boosting process, the lightest one is the interference to the vehicle radio, there is a rustling sound, like the Roewe 550 flashing lights, causing the U disk to restart, these are all due to radiation interference
Solution: Refer to the original car models with xenon lamps, such as Crown's white electric equipment. The high-voltage wires of the white electric equipment are covered with shielding nets to shield interference signals. When you test the white electric equipment, you can find that the positive electrode After the connection is completed, the negative electrode can be energized even if it is placed on the shielding net. This proves that the shielding signals of the original car are all connected and can be transmitted to the outside of the car.
Therefore, when installing a ballast, whether it is an imported or domestic ballast, there must be a shielding net. The shell of the imported ballast itself is grounded and can conduct radiation sources. Domestic ballasts must have a grounding wire, otherwise they will not be able to conduct radiation. The role of interference.
Conducted interference: Conducted interference is the key factor that really causes the driving computer to burn out. The conductive interference generated by the ballast will be transmitted back to the car through the 12v low-voltage line. After being transmitted to the car, it will cause an impact on the driving computer in the reverse direction. If the interference gathers to After a certain amount, the IC chip of the driving computer will be broken down, causing what is often called the driving computer to burn out.
Conducted interference can be filtered with a magnetic ring. Like white appliances, there is usually a magnetic ring at the 12v power input position to filter conducted interference.
