Fault phenomenon
    A modern Sonata sedan, equipped with 4-cylinder electronic fuel injection engine, there has been idle instability, high and low speed, and in the low-speed driving, the occasional channeling phenomenon. When the fault occurs, the CHECK warning light on the dashboard is illuminated.
    Troubleshooting and troubleshooting
    CHECK warning light on the dashboard light, indicating that the electronic control system is faulty, call the fault code, shown as "14", which means that the throttle position sensor signal is not normal. Remove the harness position sensor on the harness connector, observe the terminal without rust, contact is also reliable, then refer to the maintenance manual with a multimeter to measure the throttle position sensor resistance. When the throttle is manually operated by the full clearance, it is found that the resistance value does not change linearly, but the resistance value changes abruptly when the whole clearance (slight vibration) and the opening degree are not large. This shows that the throttle sensor within the sliding resistance of the phenomenon of poor contact. Replace the new throttle position sensor, remove the fault code, troubleshooting.
    Failure analysis
    The model of the engine throttle position sensor, from idle to high-speed smooth transition, the input resistance to the computer should be 0.5kΩ smooth rise to 3.5-6.5kΩ. The above fault is due to the throttle position sensor in the idle (slightly vibrating) or low speed, the output resistance value of the mutation, to the computer input error signal (equivalent to the throttle opening suddenly opened or reduced), and There is a phenomenon of abnormal engine work.