Model: Haval H6
Failure phenomenon: The instrument occasionally reports electronic handbrake failure, ALS failure, ESP failure, variable function restriction fault, and occasionally no key detection, this fault occurs frequently. When
encounters such a failure, should we doubt which aspects of the problems? The editor considers the following aspects:
① Wire harness failure
② Instrument itself failure
③ A certain module failure
④ CAN line failure
⑤ Other faults
In the diagnosis process, listen to the customer's voice first!
The customer reported that the vehicle's instrument light was on and the electronic handbrake fault, ALS fault, ESP fault, and the variable function was limited, and it was occasionally unable to start. First, the vehicle was verified for failure. After entering the station, the fault light still existed, but the instrument did not show a key prompt.
Next, take the computer to see the fault
First use the X431 detector to read the fault code to the ESP system,
1: C006208 longitudinal sensor error
2: U010087 Lost communication with ECM
3: U012887 Lost communication with EPB
4: U012687 Lost communication with SAS
5: U012387 Lost communication with SAS
5: U012387 Lost inertial sensor node
6: U006308 The steering wheel transfer sensor count error. The engine system reports
1: U012687. It has lost communication fault with SAS, and
2: U016700. It has no response to theft. Electronic handbrake system reports that the U111281 ESPCAN signal failure. Variable system report U045200 ABM message error
According to the cause of the appeal, the analysis is mostly that the CAN short connector and the connector are virtually connected, and no substantial problem is detected. Therefore, the ESP module pins are processed. Considering that the EPB report failure is due to the loss of the ESP on the network node and the failure after the ESP CAN signal cannot be received, the EPB is not processed, and all module fault codes are cleared, so that the customer can observe in the near future to see the road section, time and location where the fault occurs, and in what state, so as to collect effective information when the fault occurs in the next step.
Since the editor has no idea, thinking about such a hard-working problem, there is still a fault for repair, but the good times didn't last long.
The next day, the customer entered the station and reported that the car had an appeal failure again, and sometimes the car could not start, so he used the detector to read the fault code again. The ESP and engine system were the same as the appeal fault code, and there was a U110116 in the ESP. First, the actual car verification is carried out. When the door is opened without a key, the turn signal flashes, the locker is unlocked, and the welcome light and the instrument background light are also slight flickering, and it is not easy to detect. When the brake pedal is pressed, the instrument background light and reading light also flash. The viewing brake light customer has installed a flash brake bulb. After removing the brake, there is no flashing, and there is still slight flickering when the brake is opened and closed. After clicking the one-click start switch, the instrument occasionally shows that the instrument cannot detect smart key , and the instrument background light is black, (Figure 1)
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00000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000 The source mode cannot be converted. Check the vehicle. After the driving recorder and other radio equipment such as the access control card are removed, the key cannot be detected. However, when the keyless entry is entered, it means that the key and CAPE can communicate normally. It can be started normally with emergency start. It can be determined that the smart key, CAPA and ESCL and the engine ECU can communicate normally. However, the key cannot be detected occasionally when the keyless start is started. Read the data stream to check the antenna normally. Read the fault code: U300316: Undervoltage fault, U110116: The communication voltage is too low, and the installation and modification have been removed, so the fault cannot be detected after replacing CAPE.
③ Since the CAPE system has been checked, it is considered that other modules have an impact on it. Recall that ESP just now had a fault with low starting voltage, and CAPS also had a fault with low voltage. The generator power generation is 14.2 within the normal range, the starting voltage drop is 11.5V, and the power generation and starting voltage drop are both in the normal range. It is suspected that the current is low at the moment of starting, so replace the battery first.
④ When the ignition switch is turned on, the meter and reading light flash slightly when moving the buttons of the electric seat, and the meter and reading lights flash slightly, and the amplifier is accompanied by a bang sound. There is a similar fault phenomenon when pressing the left front door glass lifter . Occasionally, sometimes when moving the electric seat ON, the instrument background light of the glass lifter switch is also turned off. This kind of fault occurs only if the line harness is virtually connected to the amplifier, detecting the amplifier wiring harness safety and wiring harness, no abnormality is found. After the engine starts, the speed will occasionally increase to 1000 rpm. After starting, the tachometer, water temperature indicator and fuel indicator will be in the car for one to two seconds. The air conditioner and fan are not turned on. The battery is measured normally with a multimeter. After considering these factors that increase idle speed, use the detector to read the engine data flow and power generation 10.98V (Figure 2),
According to the engine ECU monitoring power generation, the instrument background light is off, the reading light and background light flash when using high-power appliances, the communication voltage between ESP and CAPE is low, and it is judged that the power cord is dummy. During the inspection, it was found that the B+ power cord of the cab fuse box was dummy and when touching this wiring harness, it was very hot. The connection piece had changed color. Let's take a look at the picture.
and there were signs of burning (Figure 4)
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has repaired so much. To sum up, learn from experience, it is conducive to future maintenance. During the startup process,
starter requires a relatively large current to maintain operation. Since the power cord of the cab is connected to the power cord, the internal resistance of the wiring harness increases, resulting in a voltage drop. The ECU monitors a low voltage fault through CAN and records the relevant fault code. The voltage drop measured at the battery is the voltage drop of the starter, not the voltage drop of the module. In the later measurement, the voltage drop should be measured on the power cord of the module. In this case, this type of Faults should find common points, from simple to traditional. When the fault code read by each module is limited, it is not to directly write the variable ECU. Combined with each fault phenomenon, comprehensively considering that the engine speed rises because the engine ECU detects that the system voltage is low, so it increases the speed and increases the power generation. BCM detects that the system voltage is low, and the background light is turned off in order to save power. The instrument has a low starting voltage to protect the hardware, so the pointer meter is cut off. After starting, the voltage rises, so it appears that after starting, the instrument will wait for one to two seconds to be normal.
