Why is it difficult to improve the refueling speed of Mercedes S320?

CAN-BUS automobile multi-channel information transmission system and its maintenance technology-Li Dongjiang's foot). When the ignition switch is turned to "on", the switch power supply terminal has a voltage of 12 V, and then when the five cruise switches of the cruise switch accelerate, decelerate, remember, clear and stop respectively, the corresponding terminals of the electronic control unit have a voltage of12 V.. The state change reflects that the switch state signal is normal, indicating that the cruise switch circuit and power supply are basically normal. Then test the circuit, power supply and switch of the brake light, and it will be all right. Next, measure the electronic throttle circuit (Figure 3). In fig. 3, pins 17 and 18 are the positive poles of the electronic throttle position motor, and pins 15 and 16 are the negative poles of the electronic throttle position motor. The measured resistance at these two ends is 2. 1ω, which is consistent with the motor coil winding resistance being less than 16. Pin 56 is the grounding wire of the electromagnetic clutch, and pin 34 is the positive pole of the electromagnetic clutch. Measure the resistance of electromagnetic clutch, and the resistance meets the normal standard. The resistance of the electronic throttle sensor is 2.237kω, and that of the position motor sensor is 2.277kω, which belongs to the normal range. No.20 needle is the positive pole of the empty contact and safety connection, and No.37 needle is the empty contact signal. Measuring 20-pin and 37-pin CAN-BUS multi-channel information transmission system and its maintenance technology —— Li Dongjiang's current resistance is 0 Ω, which indicates that the empty contact position is correct and can be connected. Pin 59 is the grounding signal for safe connection, and the resistance measured at pin 20 and pin 59 is1.35kΩ, which is also normal. After that, the 1 1 lines of the electronic throttle were measured respectively, and no short circuit phenomenon was found between them (disconnect the plug of the electronic throttle and remove the electronic throttle control unit). This shows that there should be no major problems with the electronic throttle and wiring. Disconnect the plug of electronic throttle and measure the voltage of each pin separately. It is found that the voltage of each pin is 0 V, so the fault may be concentrated in the electronic control unit (Figure 4) itself. After replacing a new computer with the same version, disconnect the plugs of the electronic throttle and the control unit, and read the fault code with the instrument when the computer is not in the position shown in Figure 4. Turn on the ignition switch and find that you can communicate with the electronic throttle control unit, and find that there is a code related to the failure of the electronic throttle control unit. At that time, I thought it might be the version and setting of the computer, and I didn't care too much. From the original non-communication to the normal communication now, it can be proved that the above judgment is basically correct. Connect the plug of electronic throttle and start the trial operation. After starting, it was found that the engine's CAN-BUS multi-channel information transmission system and its maintenance technology-Li Dongjiang's speed could not be increased (when stepping on the accelerator pedal), but only changed in the range of 1 000 ~ 2 000 r/min, which was the same as before. After stopping, the engine diagnosed itself and found that it could not communicate normally. And this phenomenon is very similar to the situation of burning out after the new computer is installed. Analysis of the peripheral circuits of the electronic control unit, part of which is the input of power supply and various control state signals, should be no problem after the above measurement. The other part is the drive of electronic throttle and the feedback signal of electronic throttle, and the drive circuit of electronic throttle is most likely to have problems. Then repeat the measurement again and find that pins 15 and 16 are short-circuited with the casing of the electronic throttle. Disconnect the plug of electronic throttle, turn on the ignition switch, and measure the voltage at the plug respectively. I found that there was no voltage at the plug, so I was sure that the controlled computer must be broken again. After careful measurement and analysis, it is found that there is a short circuit between the 15 and 16 pins of the electronic throttle and the casing. There seems to be something wrong with the electronic throttle. There is the same electronic throttle in the library. Measure the resistance between each pin and compare it with the old electronic throttle (see table 1). From the measurement results, there are two differences: first, the resistance of the motor is 4.6 Ω, while the old model only has1.9 Ω, and the new 1 1 pin is not short-circuited with the housing. This shows that there is something wrong with the old electronic throttle (Figure 5), so remove the old electronic throttle. After opening it, it was found that the insulation sheath of the internal 1 1 wire was completely damaged, and the gap between the internal lead of the electronic throttle and the casing of the electronic throttle was very small, which led to the instantaneous short circuit when the engine was shaking, and the computer was burned due to excessive circuit current. The peeling of the lead skin of the electronic throttle causes the CAN-BUS multi-channel information transmission system and its maintenance technology-Li Dongjiang's circuit is grounded with the electronic throttle housing, and the computer is damaged due to excessive current, which is the real fault cause of this car. After replacing the new computer and throttle body, everything returned to normal. Fig. 5 The measurement of joint voltage and pin resistance of electronic throttle is as follows (see table 1 and table 2) for reference. Table 1 electronic throttle pin resistance and lead voltage Electronic throttle pin resistance new, old and ω voltage, V 4 and114.6191.04512 and13 4. Kloc-0/654382 670 660 4 0.000 2 and 3 1530 1540 6 0.000 3 and1010153080.000. 000110.000120.00010 and 813601312.000148.4000. Through the reflection after the repair, it is found that the bypass is that the state between the lead wire of the electronic throttle and the engine ground wire is not measured, thus causing the above error. We propose here that, generally speaking, open circuit is easy to measure and judge, but short circuit should be recognized as positive short circuit, short circuit between lines and short circuit between lines and ground respectively. In addition, when the control unit is damaged, before replacing it with a new control unit, it is necessary to find out the cause of the damage of the control unit and carefully detect the related devices and circuits. Only after confirming that there is no problem can a new control unit be installed, which is also clearly stated in each maintenance manual.