十一月 8th, 2009 15:07
keyword: DTC decoder for a long period of time, the fault code was that many of our maintenance staff to resolve as a panacea for automotive electronic control. As long as encounter electric control of the vehicle breakdown, it is necessary to try to out-source failures, faults the code has been fixed on the car as if half; On the other hand, not a loss as to how often people do not know how to proceed. All of a sudden, many of the maintenance of books on a variety of imported vehicles to explain the failure code, fault code of access methods, detailed diagnosis seat location information and so many maintenance staff to become the preferred focus. It was rumored a certain industry, such as Automobile, such as martial arts master what THEFT like Raiders maintenance manual, what diseases doubled as long as the Raiders will be able to capture and later occasionally had the privilege to a concept, in fact, only THEFT is a Accumulated over the years writing code-fault. In recent years, with the influx of imported vehicles as well as the domestic auto joint venture companies to introduce advanced foreign models produced in the high-end car market one after another, many car repair business from hardware to software constantly upgrade, modern electronic control of vehicle maintenance Technology is no longer to make people feel less of the unpredictable. Various types of diagnostic and decoders to be equipped with the large number of Automobile manufacturers, in particular, a number of special after-sales service centers, but also a large amount of money spent to buy the original manufacturer of diagnostic apparatus, such as: SGM’s TECH2, SVW’s VAG1552, NISSAN of-the-art, and so on CONSULT Equipment. With such equipment, failure of the access code to identify and explain the mystery is not so, but the actual production, our maintenance operations but this does not become easy, even with fault code so that instead of maintenance operations Strange things become more complicated. In the end what we should do in the face fault code? I will be in Shanghai Buick sedan, for example, some fault codes related to the knowledge and ideas related to the diagnosis. Shanghai GM’s Buick production line equipment, the car is a second-generation on-board diagnostic system that is OBD-Ⅱ (OnBoardDiagnosis). Buick as a result of the pure blood of the United States, SGM It cars and other diagnostic systems in North America in 1996 after the production or sale of the car in the implementation of standards and strategy for the diagnosis of the hardware and software in addition to the oxygen sensor is no equipment in order to double unable to perform three Catalytic converter efficiency monitoring function (by the use of Chinese conditions) and the rest is basically the same. DTC’s indicated that the same method and type of early OBD-Ⅰ, if the problem is detected, the PCM will correspond to the DTC fault codes are stored in memory. OBD because the federal government is required by a standard laws and regulations, so as long as they meet the requirements of the on-board diagnostic system fault code will have almost the same format and standardized, so that makes the DTC system to sustainable development, Will be updated immediately OBD-Ⅲ launch. OBD-Ⅱ equipment in the vehicle, all of the DTC fault codes are letters of the alphabet at the beginning, followed by the number 4. Such as: P0101, C1234, B2236, and so on. DTC at the beginning of the letter that was to monitor the system’s fault: P-driven system; B system for the body; C for chassis systems; U for the network or data communication transmission system fault code. The first is the number of common code (for all vehicle manufacturers), or manufacturer-specific code. For example: 0 generally refers to the code, referring to a manufacturer-specific code. General Motors vehicles there to help you diagnose the state of technology-specific types of digital coding. The second figure that has affected the type of system failure, from the number of 1-7:1 for the fuel and air measurement system; 2 for the fuel and air measurement system (specifically loop injection system dysfunction); 3 for the ignition system or missing Tank monitoring system; 4 for the auxiliary drainage system; 5 for speed control and idle speed control system; 6 output lines for the computer system; 7 for the gearbox. Finally, the double-digit points out the failure of the system components or parts, inadequate reference here. DTC diagnostic code based on the type of OBD Ⅱ’s request, in accordance with instructions to monitor the implementation of the diagnostic systems and the severity of the failure to factors such as the DTC fault codes are divided into different types. Different types of code to set different requirements, and the diagnosis of execution only in the event and related emissions (FTP may be more than 1.5 times the requirement) so that the DTC, when the engine failure to light up the MIL light. DTC has been divided into four main categories, A, B, C and D categories, Class A and B of the DTC and engine emission levels are related. A: In the first trip to diagnose the monitoring, diagnosis and implementation of the directives of the report detected fault, DTC will light up the MIL light and storage. Class B: the second consecutive trip to run with the level of emissions-related diagnostic testing, diagnosis and instructions to detect faults, DTC will be stored but also to light up the MIL. Detected for the first time in the post-fault, B-type fault code will be ready to enter into, since B-type fault code in a state of alert in preparation for storage or a history of code. If this failure from happening again, so that the MIL light; On the other hand, through a detection system for the lifting of the DTC’s Class B state of alert. Some special conditions will allow for the lack of fire and fuel adjustment fault code DTC. Class C: for the first time in the trip and the operation of non-emissions-related diagnostic tests, at the same time the implementation of directives to the diagnosis of failure is detected, in memory of the DTC at the same time so that the light vehicle maintenance SERVICEVEHICLESOON (if equipped) to light up. D: for the first time in the trip and the operation of non-emissions-related diagnostic testing, diagnosis and implementation of the directive to detect failures , D-type storage DTC will not light up the MIL light, the DTC fault code will be the maintenance of a vehicle Diagnosis is very useful, especially when some of the drivers pointed out that while the decline in the performance of MIL was not lit. DTC correct understanding of the conditions set up electronic control system fault code is the history of the development of modern computer-controlled vehicle diagnostic system from the continuous improvement of history. From the initial brief on the output, input voltage monitoring circuit components, such as when a short circuit in the state to monitor the voltage at the time of low potential, in the open when the high-voltage lines as well as the potential mutation of the more than self-diagnostic system to set the threshold voltage , The self-diagnostic monitoring system based on the voltage lines ports and the corresponding failure symptoms correspond to the pre-set in read-only memory ROM code number to set the fault code. As a result of microprocessor information processing ability, since the early diagnosis or identification system can only be described as the failure to set a small amount of code, and fault code is also limited to the contents of the open circuit, short circuit, the signal is lost, incomplete, the work of the implementation of the components The current abnormal changes and the like. Since the failure of the content is straightforward, the fault information to be read after the general use of multimeter not be difficult to resolve. In addition, early electronic control car imports just to enter China, a variety of maintenance information on a relatively small, so at that time how to obtain a fault diagnosis code, how to find the meaning of the diagnosti
c code was indeed a maintenance vehicle electronic control the most important task. With the micro-electronics technology, computer technology strides forward, with countries close to the level of engine emissions in the harsh demands of modern electronic control of the car from the increasingly powerful diagnostic capabilities. In other words, electronic control system for monitoring requirements, as well as the number of control will significantly improve the accuracy, fault type and the number of code have gone up. Shanghai GM Buick car, for example, light powertrain (engine and gearbox) of the fault code number on the nearly 90 or so, so much the fault code allows for the failure of the contents of the statements more complete and detailed. This is conducive to maintenance technicians for the diagnosis of the vehicle, but because of the requirements of precision control, as well as diagnostic system to monitor all the requirements of the different diagnosis, fault code no longer content is not limited to voltage too high or too low voltage signal There is no simple statements, like the emerging: long-term fuel trim system Guonong, MAP performance, EGR system, and so rough location of the error can be difficult to understand the fault code. And that these failures are often set with the special requirements of the monitoring system has its specific conditions. According to the author’s experience, this time in the access code fault diagnosis, carefully read the maintenance manual to find the fault, failure to set the conditions, set up after the failure to adopt the strategy appears to be very important. For example, a certain fault conditions is greater than the speed 8km / h, TPS is greater than 10%, A / C to close the conditions in order to diagnose and unusual settings. If you would be stopped at the side of the car, running and open idling air-conditioning to find fault, as you may never be able to reproduce the fault. This is often the consequence of your thought after the end of the maintenance and carelessly remove the fault code (and indeed at that time under the conditions of the fault code does not reproduce), the vehicle will be handed over to customers. Unfortunately, the car did not soon return to the maintenance station, and the fault code and re-emergence of incredible. Such a repair can be said to be the case list goes on. In fact, many difficult to understand the failure of maintenance personnel in the repair yard after the end does not appear that once the vehicle has been put customers on the go at once to reproduce the situation that is code for the failure to set clear conditions caused by. I personally have seen the relevant because the oxygen sensor fault code and 1 week in a row to replace the oxygen sensor 3, as an EGR system fault code and replace the EGR valve, PCM even need to be replaced almost the entire engine wiring harness maintenance cases. View detailed fault diagnosis code to set conditions is of great significance: as a vehicle maintenance staff, you have to know the car’s fault in the end is when did it happen? Fault code because of what conditions trigger? How can we be their own fault simulation of the conditions? How to identify real failure has been ruled out fault code will now tell you that in the past or the car of a certain system of a certain failure, so long as the maintenance after the end of the fault code will no longer appear that failure was ruled out. But please keep in mind that failure can Code because the fault does not exist disappear, if the same fault system to monitor the program because some conditions have been suspended, the same fault code is not the case. Shanghai GM’s Buick sedans equipped with OBD-Ⅱ system as an example. To complete the system of testing all items must be at least 12min, and 12min in this period must be in accordance with the OBD-Ⅱ testing requirements: idle, acceleration, cruising, and then speed up again cruising speed, brake slide and other non-specific condition . This condition for testing, known as an OBD-Ⅱ drive or cycle of 15 working condition. Only after such a drive cycle, all the monitors were switched on before, after detection, and control modules Records under the I / M signs that the situation of the whole system of testing. As the personal driving habits, road traffic and other reasons, and in the repair after the end of the test process, if the system just monitors have not been switched on, then the fault code will not appear. Therefore, the repair work is completed in accordance with the tens of millions to set up the original code, to avoid the constraints of the monitors start testing all sorts of factors test. If there is SGMTECH2 diagnostic apparatus, then enter through a specific DTC menu to watch to monitor the state of failure is very necessary. Maintenance testing examples: case 1: BUICKGL8 commercial vehicles can not speed up to a maximum speed 80km / h. A section of the 2001 Buick GL87 Block-stop commercial vehicle maintenance, repair customers for the failure symptoms: normal idle speed, but can not afford to speed up, wide-open throttle will not exceed the maximum speed of 80km / h, and in some cases failure indicator light flashes. Use a mechanic TECH2 read PCM fault diagnostic code for P0131, that is, low-voltage circuit HO2S. According to the tips of the fault code, in accordance with the road map, the use of multimeter, HO2S overhaul of the heating lines corresponding to the oxygen sensor, ruled out because of the signal lines to short-circuit caused by the low-voltage circuit of the Signal may be. Idle run-time, HO2S signal to 450mV change from top to bottom, the only change marginally. Mechanic suspected of oil down, connected to a hydraulic table testing. Idling around 2.7kg in the oil pressure, oil pressure changes in the air when Caiyou Men also normal. According to reflect the customers, the car went to the field several times after the situation there. Taking into account the likely increase because of lead or low-grade fuel for thermal oxygen sensor caused the poisoning, they suspect that a mechanic to replace the oxygen sensor hot. After the replacement, removal of the TECH2 stored in the PCM failure of the code. In order to verify the fault really rule out the possibility that an idling car running again into the fault diagnosis code menu, the screen shows no fault diagnostic code. Just one day again return to the customer, complained that failure to return soon, and speed up the exhaust pipe in the car when it will issue a roar. Then I read the car again after the failure of the PO131 code prudent to check carefully on the fault code that diagnosis. 1. DTC to run * no conditions to start the TP, MAP, IAT, ECT, MAF, CKP sensor, the lack of fire, the fuel nozzle circuit, EVAP, EGR the DTC fault codes exist; * closed-loop command of the air-fuel ratio of 14.4 and 14.9 Inter; * throttle angle in the 5% and 40%. 2. DTC to set the conditions for normal * during the closed-loop operation, HO2S voltage signal less than 175mV or (mixed gas concentration increases) enhance the dynamic control mode fuel during the operation, HO2S voltage signal less than 600mV; * to maintain the status of each During the time up to 5s. From the above operation of the DTC’s P0131 conditions, first of all to clear the car’s engine electronic control system is basically no problem. Because, it is necessary to start the Buick HO2S system to monitor the operation of DTCPO131 testing must meet the conditions of operation: No TP, MAP, IAT, ECT, MAF, CKP, EVAP, EGR and the lack of fire and the injector circuit Fault code exist; but I also find the last time after the end of the repair to clear the fault code, DTC did not immediately return so as to be excluded from failure to repair the wrong impression of the reasons – to run PO131 diagnosis must be non-idle state. In order to further understand the failure occurred when the engine condition, TECH2 from the state’s failure to freeze the project in view the failure to set the code when the 18 engine parameters (Note: to freeze the frame is OBD-Ⅱ’s request that it be recorded in th
e memory when the DTC The engine-related parameters, to facilitate the maintenance staff reference). One throttle opening value of 88% for the engine speed 2478r/min, the engine load is 90%, to speed 75km / h. These parameters are confirmed by the customer to describe the inability to speed up, speed and poor with blinking MIL symptoms. In order to obtain the real data, with access to the fuel pressure gauge and TECH2 diagnostic test on the road and customers. When speed is less than 60km / h, GL8 this performance can, however, want a rapid or overtaking a little bit of the steep slope, the vehicle will show weakness. Customers how they are allowed to refuel the door, do not speed up the bridge on the slope, saw the fuel pressure gauge pointer constant downward fluctuations and can only be maintained at 1.5 ~ 2kg or so, TECH2 powertrain data: throttle 84% of the opening, speed 70km / h, engine speed 2100r/min, HO2S has been consistently lower than 150mV, the long-term adjustment of fuel by 26%, 83% of the engine load. Failure to reproduce the symptoms, according to the data analysis system, fuel pressure in the engine running when the large load can not meet the requirements of low oil pressure leading to dilute mixture, triggered HO2S monitors set up PO131. Back to the maintenance station, to replace the fuel pump assembly of the oil and filter after the re-trial review. Access to specific diagnostic menu DTC, P0131 fault code display through testing, this entire end of the maintenance work. 2 cases. The impact of car gearbox BUICKGLX shift, the major fuel. BUICKGLX a car, the transmission shift when there are obvious Dayton vehicles, fuel consumption and serious impact shift also increased. Fault diagnosis through access to the code, failure to show P1860, that is, PWM converter clutch (TCCPWM) solenoid valve circuit failure. Failure because the instructions are clear electronic transmission control system failure, it omitted some of the conventional automatic transmission pressure test and stall detection tests, such as mechanical steps, and transmission customers that all electrical components such as control beam, TCC solenoid valve , The shift solenoid valve and so on even have Harness Powertrain have been replaced, fault diagnosis seems to be deadlocked. Again to find the settings related to the DTC, hoping to find the answer. 1. Fault diagnostic code to run the conditions for the system voltage * 9 ~ 18V; * higher than the engine speed 500r/min, continued 5s, and did not disconnect the fuel. 2. Fault diagnostic code to set conditions * PCM command to the solenoid valve to open more than 90% of the load cycle, and to maintain a high voltage (B); * PCM command to the solenoid valve to open less than 10% of the load cycle, and maintain low Voltage (0V); * more than any one of the conditions for the existence of at least 4.3s. In order to reproduce the fault code again, I remove the original is stored in the PCM of DTCP1860, inadvertently turned off the ignition switch readily. When re-open the ignition switch, the loss of communications diagnostic TECH2 returned to the original diagnosis of the fault code into the interface, trouble-free code originally prompted the sudden failure into a code P1860. Is it just did not fault code has been completely cleared? I repeated several times to clear the DTC, strangely, as long as I open the ignition switch, the engine does not start, the fault code will appear. This is how and maintenance manual on the operation described in the P1860 fault code inconsistent with the conditions? Manual natural wrong, but obviously, not in the engine to start running the state, the automatic transmission system to monitor the TCC should be meaningless. Could that be a powertrain control module of the PCM problem? It so happened that there are 000 large car accident in the sheet metal repair, to use its PCM-loading test, troubleshooting. Moreover, the failure to find the code after the set, PCM to take measures to prohibit transmission is linked to block 4 to prohibit the work of the TCC, such as adaptive shift to freeze. Guest said fuel problem with a natural explanation.