Common faults and solutions for Volkswagen models

1. Engine stalls during sudden braking

Symptoms :

Sudden jitters during driving (like manual gears and tow gears). At the same time, the EPC and maintenance alarm lights are on, the water temperature is also increased, and the ignition condition is eliminated after the flameout.

solution :

The reasons for the EPC lamp lighting are generally as follows: The EPC lamp lighting is mainly caused by the dirty throttle body. This situation only needs to clean the throttle valve, and then it can be solved after rematching;There is also a leak in the air intake system, which causes the engine control unit to light up the EPC warning light after detecting the problem; and also the failure of the brake light switch can also cause this phenomenon;The main reason that the engine fault light is on is that there is too much carbon deposit in the throttle or the engine, and the mixture ratio is out of balance after the oxygen sensor fails. Caused by fuel.

2. Exhaust gas warning light is onFailure phenomenon 

The exhaust gas alarm light is on, and the refueling engine cannot be refueled at 3000 rpm.

Solution  :

It may be because the throttle valve is not cleaned thoroughly or the fuel injection nozzle has a slight leakage phenomenon, which causes the engine mixture to be too thick, causing unburned mixture to enter the exhaust pipe, which eventually causes poisoning of the oxygen sensor. The resulting exhaust emission light is on.

3. Passats don’t go on, the gears are not displayed Solution :

The computer detected that the dual clutch transmission control unit (J743) could not be entered. Check the J743 power supply circuit according to the circuit diagram. It was found that the 30 A fuse SB 16 0743 power supply fuse in the fuse box of the engine room was blown. Replace the fuse Wire, immediately blow, check the line between fuse SB16 and J743, no abnormalities; remove J743, found that the wire connector part on the back has been burned. It means there is a short circuit in J743.

Troubleshooting : Replace J743 and rematch

4.High water temperature Failure phenomenon  : There is oil in the coolant.

Solution  :

The oil cooler sinks, and the oil enters the cooling system, causing oil pollution. After replacing the oil cooler, the fault still exists. After replacing the automatic transmission oil cooler, the fault is eliminated. Cause of failure: The internal of the cooler is damaged, and the pressure of the automatic transmission oil is higher than the pressure of the cooling system, so that the automatic transmission oil penetrates into the cooling system, resulting in high water temperature.

5. White smoke after startupFailure phenomenon :

After the cold car and parking for a period of time, white smoke is emitted, and the hot car failure disappears a little.

Cause of failure 

The leakage of lubricating oil in the cylinder pad or turbocharger causes the oil to not burn completely and emit white smoke;

Solution :

First check that the coolant is not missing. At the same time, open the expansion kettle and start the car. Observe that there is no backwater phenomenon, indicating that there is no major problem with the cylinder pads;After starting the car, observe at the same time, and found that the white smoke will disappear for a period of time after starting, and the white oil pressure should be constant after starting the car. According to this phenomenon, it is impossible to leak the oil from the turbocharger.Only the secondary air injection system worked for a period of time in the cold car, and the secondary air control valve air supply pipe was removed to find that the organic oil was flowing out of the pipe joint;At this point, the problem has been found. After removing the secondary air jet pump and the air supply pipe, there is a large amount of oil. Clean the internal oil and the fault disappears after loading.This failure is caused by the car body turning over during the accident. The engine oil enters the pump body and the pipeline through the air supply pipe of the secondary air injection pump. The engine oil is discharged into the exhaust pipe through the secondary air control valve, thereby generating white smoke.

6. Polaris has poor acceleration, insufficient power, and high fuel consumption

Solution :

First use VAG1551 to get the fault code. There are two fault codes, which are the oxygen sensor and the throttle position sensor. Since the gasoline in our country is leaded gasoline, the damage to the oxygen sensor is a common fault. Remove the spark plugs, and the four spark plugs are all reddish-brown. It indicates that the lead content of gasoline is very high. Check again that the three-way catalyst has been poisoned and damaged.

Troubleshooting  :

 Clean the engine oil circuit, replace the spark plug, three-way catalyst, replace the leaded gasoline in the fuel tank, add unleaded gasoline above 93 #, normal troubleshooting of road test