Failure phenomenon: a 2008 annual Excelle 1.6 L sedan, mileage 7 000 km. Say users, remote car lock car without chirping alert tone, the buttons on the left front door can not open the trunk lid, interior lights and luggage compartment lights are on, the engine stalled and the tachometer is not zero mileage vehicles AB table after starting the auto-zero.
examination Analysis: After the maintenance staff pick, the first impression is how the new car there are so many problems? Real vehicle examination revealed the following: ① remote control car central locking lock can work, but not into the security state; ② can remote control to open the trunk lid, and anti-theft speaker beep alert tone, but the trunk lid open button on the left front door (FIG. 1) failure; ③ and the trunk room lamp does not light; ④ after the engine stall, the tachometer needle is not reduced but remains at the position of stall speed, mileage AB table shows the value of 0 km.
According to the author of maintenance experience, the first three have ever encountered failure phenomenon, there is a definite link between these symptoms, but the fault of the instrument as if no link between the other symptoms. The car’s mileage little, should not have so much trouble, decided to see the circuit diagram to determine whether there is common ground between the symptoms, and found that the fuse EF4 engine compartment fuse box were open motor for the trunk lid , the lock pin switch, interior lights, luggage compartment lights, and audible warning module B + instrumentation to provide constant power. Real car checked again and found that the fuse has been blown EF4.
Since the luggage compartment lamp is relatively easy problems Excelle sedan, then first check luggage compartment, the luggage compartment lamp was found (FIG. 2) lampshade has burst, causing the bulb ran around in the socket. Remove the lamp, the lamp socket can be seen at the positive terminal metal ablation obvious signs, point of failure so far confirmed.
Troubleshooting: by examining the body sheet metal and paint for determining the vehicle rear collision has not occurred too. So claims the luggage compartment lamp and replace the fuse EF4, test confirmed failure were excluded.
reviewed: For the case where a plurality of systems of simultaneous failure of the vehicle,First, you should consult repair manuals and schematics, if we can find common points of failure from the phenomenon of the investigation and then you can play a multiplier effect. After EF4 fuse blows, find the user’s own four symptoms, indicating that the degree of awareness of vehicle users has increased, which also requires maintenance personnel should continuously improve their professional level.
Failure phenomenon: a 2008 annual Excelle 1.6 L sedan, mileage 69000 km. According to users to reflect the car’s speedometer in the instrument no indication, driving taxi and sometimes appear flameout phenomenon.
check analysis: Check the car’s maintenance records, three months ago, I got done in a major accident repair, pick up the car the next day there was no indication speedometer and moving slide flameout phenomenon It was accompanied engine fault lamp lighting phenomenon. Shortly after arriving in stalled because taxiing maintenance, then the engine control unit stores the vehicle speed sensor fault code, fault disappears in line inspection process. A vehicle speed sensor maintenance personnel suspected a signal line terminal metal fitting place, may be due to the wire harness is pulled in the inspection line fault disappears, then the user continues to observe the recommended use.
the vehicle into the plant because the same failure, we must find the real cause of the failure. First using the scan tool TECH2 check, no fault code stored within the engine control unit, driving speed signal in view and engine instrumentation system stream remains at 0 km / h, the instrument does not move in the odometer. With reference to a circuit diagram of a vehicle speed sensor (FIG. 3), a vehicle speed sensor measuring a voltage B pin plug, and when the ignition switch ON voltage of 0 V (normal should be 12 V), the engine control unit ECM disconnect the harness connector C108 and C202, a vehicle speed B voltage sensor plug pin becomes 12 V, ECM back into the harness connector B after the pin has been pulled back to the voltage 0 V (before examination has confirmed that there is a vehicle speed signal pin B normal voltage 12 V). Finally, the B plug unplugging the meter, then measuring the vehicle speed sensor B plug pin voltage is 12 V and no longer change, then test to confirm the vehicle speed signal is normal, then suspected fault within the instrument.
At this point I take into account the car is the car accident, has been dismantling the dashboard, so the possibility of relatively large harness problems, you should carefully check the instrument harness. Thus the instrument is removed, it was found that the harness connector B is clamped meter rear instrument panel fixing bracket, wherein the sheath has three wires are sandwiched broken (FIG. 4), wherein there is a vehicle speed sensor signal lines (green / white ).
Troubleshooting: good skin broken line dressing, road test no longer malfunction.
reviewed: vehicle speed sensor intermittently grounding signal lines, resulting in 12 V voltage signal on the signal line is shorted to ground, the engine control unit can not receive the frequency varying signal lines, so there are data flow speed signal is 0 km / h and Symptom misfire during coasting. Vehicle speed sensor is a Hall sensor, the engine control unit via a vehicle speed sensor signal terminal, the engine control unit converts the frequency signal generated by the vehicle speed sensor into a vehicle speed signal, it is noted that must be measured vehicle speed sensor signal when the line voltage measurement sensor plug is disconnected. Bovine Yingwei
(bovine head loss)