Troubleshooting Throttle valve switch And How It works

Throttle valve switch
Throttle valve switches are used to determine the position of the throttle valve. They are attached directly to the throttle valve axis. The respective switch positions are transmitted to the engine management control unit and contribute to the calculation of the required fuel quantity. 

Function


There are two switches in the throttle valve switch which are actuated via a switching mechanism. The two switches provide the engine management control unit with the information it requires about the engine operating states idling and full load in order to guarantee accurate calculation of the required fuel quantity.

Effects of failure

A faulty throttle valve switch can result in the following: 
■ Engine dies during idling 
■ Engine is bumpy at full load 

Reasons for a faulty throttle valve sensor can be: 
■ Mechanical damage (e.g. due to vibrations) 
■ KContact fault at the electrical connection (corrosion, humidity) 
■ Contact fault at the inner switching contacts (humidity, soiling)

Troubleshooting

The following test steps should be taken into account during troubleshooting: 
1. Check the throttle valve switch to make sure it has been installed properly 
2. Check whether the switching mechanism is actuated by the throttle valve shaft (with the engine at a standstill move the throttle valve from the idling stop to full load stop position to hear whether the switches are actuated) 
3. Check pin connection for a correct fit and any soiling 
4. Test the switching contacts using a multimeter: 

■ Idling switch closed: Measurement between pin 1 and 3. Measuring value = > 30 MOhm. 
■ Idling switch opened: Measurement between pin 1 and 3 (note: open the throttle valve slowly during measurement until the idling switch opens). Measuring value = 0 ohm.

■ Full load switch opened: Measurement between pin 1 and 2. Measuring value = > 30 MOhm. 
■ Full load switch closed: Measurement between pin 1 and 2. Measuring value = > 0 Ohm.


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