Cars damaged when the computer can pull to repair the computer, the following test tool used to launch x431, lexia3, mb star. Here are some computer malfunction:
The first is part of the computer power supply failure. Generally because the vehicle charging, the charger voltage regulation due to too high, or reversed polarity or charge while opening key, or even start the motor, or engine during operation, causing the battery connector loose generator directly to your computer board power supply and other reasons. This will generally burn high-power components such as voltage regulator diode, change can be relatively easy to repair.
The second is the input / output part of the fault. Amplification circuit element is usually burned, sometimes accompanied by follow-steel lines blown circuit board. For example: a repair shop in Taiwan and USA Chevrolet sedan on a renovation of paint and found that the engine can not start, and if you open the keys over time, gasoline from the exhaust pipe, oil pan, etc. overflow. Open the keys and found that all six fuel injectors are fully open state, gasoline directly from the nozzle into the cylinder, flow over after the overflow, check the external circuit found no problems, it can be concluded that the output of the computer control failure. Detection methods can be used is launch x431. Open the computer case examination revealed nozzle control signals on the amplified high-power transistor has a breakdown short circuit, causing power nozzle that is normally open state. Replacement of a similar type of transistor and clean up after replacing engine oil, the engine can operate normally. To note here: Many EFI vehicles through paint, then start all kinds of faults often occur, because after the car interior through the paint, especially in circuit accumulated heat within the device and heat, and the heat from the inside slowly comes out of the depths, and electrical equipment to work easily in the high temperature failure. Therefore, do not immediately drive the truck out after baking, but should be cooled through the full start, if the production of stress need to free paint room, you can use human power to push the car, let it cool down, the re-start.
A third part is the memory failure. A total of four kinds of memory, read-only memory (ROM) is used to store computer monitoring program that the computer itself, some of the procedures that must be run. Programmable read-only memory (EPROM or EEPROM) is mainly used to store for the implementation of devices or other control devices for the control program. Such as: fuel injection control, ignition advance angle control. Idle speed control and self-diagnostic procedures. Random Access Memory (RAM) for temporary storage of data from various sensors for CPU use; also the fault code storage systems. Random memory contents will disappear after the power failure. Need to know this detection technology lexia3. Adaptive memory (random access memory belonging to a) for the computer’s “self-learning” and in accordance with vehicle speed, automatically adjusts the parameters. Such as “idle learn” and so on. To eliminate the programmable memory (EPROM or EEPROM) problems can be replaced, need to find a well-known memory chip with program content, buy a blank chip with the model, by writer, from the read the original film program, and then to write to a blank chip, new chip can be copied, and then the new chip into the computer. But most car manufacturers are set up to only copy 3-7 times more than the number of after no longer using, and some manufacturers make chips by means of an encryption can not be copied.
Last case is a special failure. Off by the flooding of vehicles, computers plate corrosion occurs, the component pin circuit, adhesion or component damage, can repair or replace components by check. For example: a repair shop received a Cadillac car repair, fault phenomenon: when the normal operation of the engine if the on / off headlights or other electrical equipment, exhaust pipes blasting phenomenon occurs, the exhaust pipe can be serious burst. Better detection technology is mb star. The inspection found that the external circuit is not the problem, suspect faulty computer, open the computer box carefully monitored and found that a ground wire for corrosion circuit, the grounding line is the oxygen sensor signal shielded cable inside the computer grounded through the location, because Duanlu to shielding failure, caused by oxygen sensor signal interference caused by other appliances, with a tin solder through time, that is back to normal.
These are some common computer failures will be encountered in the actual work a variety of fault phenomena, as long as a clear principle, and acquire a certain way, analyze specific issues, finally has a solution.