Fault description:
When the vehicle is stepped onclutchWhen shifting gears or coasting in neutral (the accelerator pedal is not depressed), the engineRotating speedThere are two situations where the rotating speed is higher than the normal idling speed as follows:
1. The speed increases but does not exceed 1600r/min;
2. The speed increases and exceeds 1600r/min or more.
cause of issue:
1. Coolant temperaturesensorThe signal is wrong and the idle speed increases
Due to the coolant temperaturesensorOccasionally a fault occurs, and the coolant temperature that is far lower than the actual temperature is transmitted, causing the control unit to mistakenly believe that the engine is working at low temperature, and the wrong multiple air intake and multiple fuel injection, resulting in an abnormal increase in idling speed, up to 2000r/min above.
2,AccumulatorThe lack of electricity causes the engine idling speed to increase
Due to the serious power loss of the battery, when idling is running and the electrical equipment is turned on more often,DynamoThe power generation efficiency is not high, resulting in insufficient power supply for the engine control unit, and fluctuations in the engine speed, which can be as high as 1400r/min-1600r/min.
2. The speed increases briefly when shifting gears
PASSAT2.0 uses electronicsThrottle,ThatswitchThe speed and angle are not like the previous mechanical sectionValveThat only depends on the opening of the accelerator pedal, but also comprehensively consider the stability of the engine operation and environmental protection issues. Therefore, even if the accelerator pedal is released, the opening and closing of the throttle valve will be delayed according to the previous state of the engine. In addition, operating factors such as the speed of clutch disengagement during gear shifting can also cause the engine speed to rise temporarily. For an EFI engine equipped with an electronic throttle, the engine speed will increase slightly when shifting gears, but it will return to normal soon. This is a normal phenomenon. It is due to stable operation and environmental considerations. Determined by characteristics. In this case, the engine speed can be increased by about 500r/min.
After-sales service solutions:
1. For the idling speed increase of about 1600r/min or below, please check the following:
üCheck whether the battery has power loss, if the power loss is serious and the voltage is lower than 12.35V, replace the battery;
üCheck the intake pipeline and whether there is any air leakage in the downstream of the air flow meter. Vibrate the intake pipe, observe whether the engine speed fluctuates, and if so, find the leak point and deal with it accordingly;
üWhether the user has modified the circuit, and whether the ground of the modified electrical appliance is close to the ground of the control unit. If so, move the grounding point far away to avoid interference to the engine control unit.
2. If the idling speed increases above 1600r/min, please check the following:
üCheck whether there is a 16502 fault record in the engine fault memory, and replace the coolant temperature sensor if there is;
üCheck the intake pipeline and whether there is any air leakage in the downstream of the air flow meter. Vibrate the intake pipe, observe whether the engine speed fluctuates, and if so, find the leak point and deal with it accordingly;
üWhether the user has modified the circuit, and whether the ground of the modified electrical appliance is close to the ground of the control unit. If so, move the grounding point far away to avoid interference to the engine control unit.
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