Topic 6: Failure of Lavida remote control key
Car model: langyi
Failure phenomenon: key remote control function occasionally fails
Maintenance situation
After checking that the function of this car fails in remote control key, it will return to normal as long as the key matching is performed again, but the problem will occur again after a period of time (several days to several weeks are uncertain). The transmitter, BCM, door control unit and frame lock have been replaced successively. Check that the vehicle has not been modified and the fault cannot be eliminated.
Technical support
1. On-site inspection the only remote control key of the car is in a state of failure;
2. Read the key ID code stored in the BCM controller is 9 0C1A5EA(Hex), which is the same as the key ID, indicating that the key matches the BCM controller correctly. At this time, there is no need to re-match the remote control, and only the remote control synchronization method is needed to restore the function;
3. Synchronize the remote control (press the unlock button on the remote control key first, and then unlock the car with the key head within 1min), which is invalid. Read the BCM data block to check whether the controller has received the remote control signal. When you press remote control key, remote control push-button control shows "not operated" and the key number shows "1", after releasing the key, keep it as "1", which is abnormal (Table 1) ;
4. Check the BCM wiring harness. The external line of the vehicle BCM controller is damaged due to modification, which affects the normal operation of BCM. Replace BCM controller and remote control transmitter, encode and match BCM controller according to factory requirements, and troubleshoot.
Maintenance suggestions
When encountering electrical system faults such as remote control and centralized control door locks, check whether the vehicle has been installed or modified first. The installed devices or circuits may affect the working status of the electronic components of the original vehicle and cause faults.
Topic 7: Langyi tire pressure monitoring system warning light bright
Car model: langyi
Failure phenomenon: instrument tire pressure monitoring system warning light bright
Maintenance situation
1. Check that there is a fault code in ABS(03): 01325 tire pressure monitor control unit has no signal/communication static;
2. Check that the four-wheel tire pressure is normal.
Technical support
Method 1: Use diagnosis equipment to select the guiding function and enter the brake device ", select" tire-inspection-Display/tire pressure alarm "and select" tire monitoring returns to the initial state "(Figure 11) when you follow the prompt to operate the" possible feasible operation "step, after that, continue to follow the prompts until the end.
Method 2: Use diagnosis equipment to select vehicle self-diagnosis, enter ABS(03), select basic settings (006), execute channel 42, delete the fault code, and turn on the ignition switch again, press and hold the "SET" key 2s for tire pressure calibration.
Topic 8: The fan often turns after the Langyi flameout
Car model: langyi fault phenomenon: the vehicle cannot start, occasionally.
Maintenance situation
1. On-site inspection: 10 minutes after the vehicle is turned off, the fan often turns, resulting in the battery running out of power and the vehicle cannot start;
2. Diagnosis without fault code storage, check water temperature sensor, air conditioning pressure sensor, fan control circuit related plug, no exception;
3. Handle the touchdown of fan controller and engine control unit. The replacement method has been used to replace the J271 relay successively. The fan controller, water temperature sensor, air conditioning controller and engine control unit still fail.
Technical support
1. On-site inspection: The vehicle is normal and the fault cannot be reproduced. Considering the occasional failure, the site is analyzed through user description and the dealer's previous inspection and maintenance situation;
2. If the fan often turns after flameout for 10 minutes, it must meet the signal of J293 without engine (T8 0/2 2 feet) and the 2 feet of J293 with electricity. According to the customer description, when the car fails, the No. 2 foot of J293 has electricity;
3. If No. 2 foot of J293 has electricity, it must meet that SC44 has electricity and J271 relay is closed. According to the report of the maintenance station, when the fault occurs, pull off the J271 fan and stop rotating, thus judging that there is no short circuit in the line after SC44 fuse. The cause of fan rotation is caused by J271 suction;
4. There are three situations that cause the suction of J271: first, the line of pin 4 of relay J271 is short-circuited with the ground wire; Second, the internal grounding of the control unit of the second engine; Third, the combination of relay itself;
5. The engine control unit and relay have been replaced in the maintenance station. Suspect that there is a problem with the line and check that there is no exception in the wiring harness. According to the reaction of the maintenance station: when the engine control unit is unplugged, the fan will turn normally, and make sure that the 4th foot of J271 is short-circuited with the ground. Considering that there is no wiring harness accessories in the maintenance station, the flying line shall be processed on site, and the engine controller shall be replaced for troubleshooting (Figure 12).
Figure 12 fan circuit diagram
Maintenance suggestions
1. When the cooling fan control unit J293 cannot receive the signal of the T80/22 foot of the engine, the fan will enter the emergency mode and keep running normally;
2. When the vehicle is off, it should be noted that J271 still has about 10 minutes of delayed power supply (engine ECU control grounding). At this time, the engine evaluates the vehicle status and determines whether the fan is running;
3. According to Figure 12, if the fan turns normally after flameout, two conditions must be met: first, J293 cannot receive the signal of T80/22 foot of the engine, second, t4p/2 of J293 has power supply (T4p/2 power supply path is A & rarr; J271 & rarr; SC44 & rarr; T4p/2).
4. The duty cycle signal of T80/22 and the T4p/2 power supply line of J293 should be carefully considered. Only by understanding the basic control logic of the fan can we be targeted and avoid blind replacement.
Topic 9: Langyi OBD light on
Car model: lavida 1.6
Failure phenomenon: the OBD light is on, and there is a buzzing noise at gasoline pump.
Maintenance situation
1. Check 01-there is a fault code in the engine electronic device: 00370 P0172 cylinder column 1 fuel measurement system is too concentrated intermittent type;
2. When idling, observe the engine data block and find that the fuel injection pulse width of the car is too small;
3. Measure the gasoline pressure. The idle speed is 6.2bar(1bar = 105PA), which is too high;
4. Focus on checking gasoline filter and find that the car is wrongly equipped with Polo's steam filter (6q0 201 051 C) ;
5. Replace the correct steam filter (180 201 511) and solve the problem.
Maintenance suggestions
The Lavida 1.6L/2.0L gasoline filter has no pressure regulator inside and is usually installed within gasoline pump, while the Polo car has a pressure regulator inside. The incorrect installation of steam filter with pressure regulator in Langyi car will lead to the situation that two pressure regulators are connected in series in the oil return pipeline, resulting in the increase of oil inlet pressure and the increase of fuel charge, resulting in the above failure.
