Jetta dual fuel taxi EPC light is on, and the fault light is on.

Check the electronic throttle body. If the throttle is too dirty, clean the throttle and make basic settings. There are problems in various components or circuits of engine electronic throttle system, which can generally be found by traditional electrical detection methods. The only thing to note is that the brake switch is an important part of the whole electronic throttle control system, so don't ignore the inspection of the brake switch. There is also that the oil should be filled in strict accordance with the standard. Too much oil will affect the concentration of mixed gas, resulting in abnormal lighting of epc. Too low cylinder compression pressure can also lead to such failures.

The reasons for this are as follows:

There is a leak in the air intake system, which causes the engine control unit to light the epc warning light after detecting the problem. If there is a leak in the crankcase ventilation system, this fault may also be caused. Serious or obvious vacuum leakage is not a problem. The control unit cannot effectively detect a slight leak. If the compensation adjustment made by the control unit exceeds the limit allowed by the internal program of the control unit, the control unit will judge that there is something wrong with the electronic throttle system and the epc fault light will light up. However, the actual reason why the epc light lights up in this process is not caused by the functional problems of the electronic throttle control system itself.