Chery Automobile Maintenance notes 2

Fault 1

an annual tiggo 2007, SQR481 mounted engine, matching QR523 type manual transmission, the user is reflected in the other car repair shop is replaced with a timing gear, after the engine failure warning light has been lit, the engine speed and the acceleration must not exceed 4 000 r / min.


After receiving the vehicle, determined, as a user of the determined failure. Maintenance staff for the first connection failure diagnostic system for detecting the engine control, the engine control unit device displays the fault codes stored ldquo; P0341mdash; mdash; camshaft position sensor signal is incorrect rdquo ;. According to our experience in the maintenance of the vehicle, the control strategy of the engine control system of the vehicle, when a fault occurs camshaft position sensor failure, the engine will be difficult to start the engine maximum speed and the symptom 4 000 r / min, but super while the engine control unit stores the fault code P0341. By comparison, the fault symptom and the fault symptom car camshaft position sensor (FIG. 1) Failure exactly. After

The author performs the removal operation fault code, but as long as a start of the engine, a fault code will appear again, the interruption of the current real fault code. For this reason a fault occurs due to code comprising: valve timing is incorrect (the relative position of the crankshaft and camshaft is incorrect), a camshaft position sensor circuit fault, camshaft position sensor failure itself, the target wheel position signal and the engine control is incorrect cell internal fault.

FIG. 2

Since the car is a problem in the replacement of the timing toothed belt, I suspect engine valve timing mechanism is incorrectly assembled. So I press SOPs special tool recalibrate the valve timing, the engine failure warning light is still not extinguished. After checking the relevant circuit diagram can be seen, three lines camshaft position sensor were ground, 12 V power lines and signal lines. Was measured using a multimeter, power the sensor, a ground and a signal line are normal, no disconnection, short circuit and virtual access phenomenon. Accordance with the principle from simple to complex, first try to pass for a camshaft positionSensor, but no effect. Given the possibility of damage to the engine control unit is relatively small, it is not replacing it. After timing tool assembly in place, see the target wheel position, I feel there are some unusual target wheel position. And because of the intake cam target wheel for the interference fit, previously did not pay much attention to the exact location. In order to determine the target vehicle Lun position is correct, I find a comparison with the car. After installing the tool timing, by comparing with that of the target wheel position difference of about 90deg; (FIG. 2, FIG. 3). Thus, the fault can be determined that the vehicle caused by changes in the position of the camshaft position sensor target wheel.

Figure 3

After replacing the intake camshaft assembly using clear DTCs fault diagnostic, test engine speed can be up to about 6 000 r / min, failure to completely eliminate.

Summary: The car camshaft position sensor and the camshaft target wheel for the interference fit, in general, does not change the position. The car camshaft position sensor target wheel position will change the reason, most likely caused by the repair shop at the timing proofreading appropriate timing with a screwdriver to pry the target wheel proofread. The car into the front end of exhaust camshaft journal has a hexagonal wrench is rotated by 24 mm opening in the timing toothed belt removed, if desired cam shaft, can only be achieved by this method. Other actions could have adverse consequences, would like to service colleagues attention.

Fault 2

2009 annual Chery a car 2 mounted SQR477 engine, matching QR515 type manual transmission. Users can only reflect the remote control to unlock the car and operate the luggage compartment, can not lock operation.

Figure 4

car remote control signal receiving apparatus as BCM (FIG. 4), while also BCM and the glass door and the whole car lifter large part of the electrical control. Car remote control strategy is: when the key aside from the ignition switch can be unlocked and the latching opening operation of the luggage compartment; if the key is in the ignition switch, in order to prevent erroneous locking key in the car, only and unlocking the luggage compartment operations (a luggage compartment opening only when the vehicle speed is less than 10 km / h). In theAfter the solution of the remote control strategy, the author analyzes the possible causes of failure vehicle travel includes a key switch (FIG. 5) made card, where the presence of short to power, and the limit switch key BCM internal fault lines.

Figure 5

First of fault diagnostic use BCM detects no fault code display device in the system. Then reads the data stream found, regardless of whether the key is in the ignition switch, showed key is inserted. Normally, when the stroke of the car key into the ignition switch, is sent to the BCM a battery power supply signal, the key switch may be turned off key stroke artificially allocated state analog. After the trip switch OFF key, the remote control is still not closed, limit switch indicates that the fault is not in the key. I use the test limit switch key pin lamp examination leading to the BCM, the lamp can not be lighted again. However, measured with a multimeter the terminal voltage of a battery is present, also found in the inspection process during the test lamp connected to the signal line leading to the BCM, actually can perform normal operation of the locking and unlocking limit switch key. This situation is even more described key switch place the power stroke slight short circuit. Upon inquiry, the user was informed that the car is at fault after the paste produced by Solar Films.

The author then removed A-pillar trim, it was found that there are traces of water leading to the BCM connector. After drying with compressed air, test troubleshooting. In this case the key again measured position switch signal line leading to the BCM, when the key is allocated, the signal voltage is about 1 V.

Summary: As personnel during improper operation when foil, leading to the key position switch leading to the inlet connector BCM short circuit is generated, so that the BCM has been to identify key into the ignition switch, resulting in the remote It can only be unlocked and not blocked. Because it is short-circuited so that water is only a virtual voltage, when the inspection test light, through the test circuit is formed so that the lamp circuit to generate a voltage drop, so that they can BCM normal operation. This failure to exclude smoothly thanks to the remote control car strategy more clearly, we hope this failure to give colleagues a little inspiration.

(Qin Zhigang)

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