New car batteries can be used for four to five years, during which it is no problem to start the engine fire. However, there may be times when the owner will park the car for about a week because of an outing, in which case the start-up voltage provided by the battery is no problem. If the vehicle has been parked for two to three days without electricity, this means that the vehicle is malfunctioning and needs to be repaired。
The owner of a vehicle, the mass of the population, came for repairs and was purchased in 2015 and travelled 150,000 kilometres. The customer-reaction vehicle had no electricity for two days, even if it had been replaced with a new bottle, and no electricity for two days。
Analysis of causes of malfunction
There were three reasons for the failure, the first being that the generator did not generate power and that the generator recharged the batteries, in addition to the electrical equipment provided after the engine had been activated. If the generator does not generate the electricity, the electrical equipment used to power the engine after start-up is powered by batteries, and the electrical power of the vehicle is large, the battery will soon run out。
The second reason is the failure of the battery itself. The first consideration is the failure of the battery's inner polar oxidation short circuit, but the battery is new and should not be due to this, and it may be damaged by a failure of external electrical circuits or connections。
The third reason is the electrical failure of the vehicle. In-car reading lamps, large lights, navigational multimedia equipment and control units, etc., as well as the purchase of electrical appliances for the vehicle。
Fault point judgement
The battery detector was used to test the cylinders, showing a 95 per cent lifetime and the test results were excellent, indicating that the batteries were in good condition. The inspection of the generator's output voltage of 13. 5 v at glitch speed and the output of 14. 3 v at speed of 2,500 indicates that the generator works well. If the output voltage is less than 13. 5 v, it is recommended to inspect the generator's wiring and wiring column; if the output voltage is greater than 15 v, it is recommended to inspect the voltage regulator。
The battery is good and the generator is good, which can only be explained by the failure of electricity on the body equipment, which is then measured using instruments. The leak refers to the passing of electrical equipment in the vehicle after the key switch was shut down. As a general rule, all electrical appliances were shut down by the vehicle's shut-off, and it was normal to leak electricity below 50 ma after computer hibernation。
The following methods are used to detect power outages: a direct current stream using one-size-fits-all meters, the removal of the battery's negative poles, the use of one-for-one red cousins (20a slots) for contact with the negative poles, and the holding of one-for-one watch pens on the other, linking the one-for-all arrays to the entire circuit, as shown in the figure below. If the currents measured were too large, it would be possible to determine which circuits had problems by pulling out fuses and relays。
The second method is to test with current pliers, although the tool is less used, with the advantage of detecting occasional leakages and detecting data of long-term dynamic variability. The third is the guiding function of a diagnostic device to check the state of hibernation in the control units under hibernation。
In the absence of dedicated tools, the first method of measurement was used. As can be seen from the figure below, consumption currents in vehicles are measured on a universal scale, which is the static current of the vehicle, which is not used by external appliances and which passes through the body circuits only with small currents. To measure this hibernation current, four doors, trunks and engine compartments will need to be closed and the storage batteries will have negative poles for more than 15 minutes, leaving vehicle control units and bus communication systems dormant. As can be seen from the figure, the measured figure is 0. 645a (645ma), which indicates a leak in car appliances。
Search for leaks
Knowing the failure point, the first step was to find out all the suspected places and, after communicating with the owner of the mayton vehicle, to learn that the equipment behind the vehicle consisted of gps, carlog, mobile phone charging interfaces, re-routing of navigation, etc. As a result, only one gps leak was found to be large, but gps had to open the key to work, so the reason was excluded。
The second stage of the screening, which was encountered, was also prone to electricity leaks, such as radios, seat switches (bek's old junta), indoor lights (the golden cup was met), wind fans (caused by the water in the audi's a4l safety box), ignition switches (keys can be pulled out in two locations), generators (bek's new top), fuel pump modules (which met a popular cc), etc., are still not unusual。
The third step was the use of a diagnostic computer to detect fault codes to detect suspicions, and the use of a diagnostic computer to clear the failure codes before reading them, which revealed that only three failed codes were available that required learning to match after a power outage, as shown in the figure below。
The fourth step uses the last method, which is to be judged by the extraction of fuses and relays. A test light to measure electrically available fuses was used, resulting in the removal of the cabin safe, and the absence of any electrical fuses on the main driver's safe, at a minimum of about 0. 5a. Then the relays were pulled, and the same data was pulled。
This car leaked at 1:00 p. M. Yesterday afternoon, the owner said he had to come to get it at 3:00 p. M. What's that? Thus, the method of pulling out the computer plate plugs, albeit at a very small rate, could hopefully be tried, and the engine computer plate, the body module and the abs pump plugs were pulled out and did not work。
Finally found the reason for the leak
The idea was turned into a headless fly, and there was no way to get ready to go to the public 4s. He then asked a friend who had been working on the car for a long time, consulted him, told him everything he had checked, and he could not give him a strong answer and asked me to check the failure code. I've checked, the location of the check is checked, but that's it. There is no other way but to restore all the equipment that was removed from the vehicle to its original condition, and only three of the first ones would have to learn to match the failure code。
The window glass lift and down study, time setup and radio setup were followed by a run-out of 5 or 600 metres until the failure light went out and the failure code was removed. When the test vehicle was returned to the factory, the failure code was checked with a computer, and a back window elevator button was suddenly found to be unreliable。
The elevator in the back window is checked by pressing a key, as indicated by the failure code. The right back window window window was found to be stuck down, unable to bounce, trying to pull a few times. It was stuck down, and the switch appeared to be broken。
The discharge was immediately measured again, and when the switch was pulled back to normal position, the discharge was 0. 024a, as shown below. Putting the switch down at the lowest level would be 0. 645a at all times. At last, the reason was found, and the sourness was simply inexplicable. It was 2. 30 p. M. And immediately ordered the warehouse to purchase a switch to replace it, and after replacing the right back window window window up and down switch, the failure was resolved and the client finally caught up with the vehicle at a critical time。
Summary of reflections
The main reason for the mayte malfunction was that the right rear window lift was stuck in the lowest position, which was equivalent to being in use, and when the owner dropped off the window, it was supposed to be always in control of the window to the lowest position, so the point of failure was more difficult to detect。
The latter was analysed by searching for the circuit chart of the maytem model, which had a body control unit bcm connected to the right front window control module through the can bus, and the right front control module controlled the right back window control module through the lin line, thereby raising or lowering the window. In the case of a back window control switch, in the case described above, there would be a blackout. The damage to the left front window and the right front window control switch does not lead to a blackout, which is expected to be known to the owner's friends。
The one-size-fits-all instrument used in the maintenance process to detect leakages is not really suitable, except for the one-size-fits-all measurement, which is not accurate, and the other, which can easily lead to the initialization of electrical equipment through the extraction of relays and fuses, which takes a lot of unnecessary time, and the second and third methods of measuring leakages are recommended。
