Signal Wave Form & Data

This figure shows the wave form at terminal 4 of ECTS at idle RPM.

Fig 1: Identifying Signal WAVE FORM

Courtesy of HYUNDAI MOTOR CO.

1. In case the voltage of ECTS is always 4V.

   Possible cause: Open ground circuit Open inner circuit of component

2. In case, when engine is cold, the voltage is below 0.5V.

   Possible cause: Short between PCM and sensor Faulty PCM

When checking the wave form, watch carefully if there is any sudden change in signal.

The ECTS and IATS signals should be smooth and continuous without any sudden changes. When the engine is cold, the ECTS and IATS signals should look similar, depending on the ambient air temperature. After warm-up, the IATS signal should not changes significantly, while the ECTS signal should drop. This indicates that the normal increase of the engine coolant temperature is larger than the normal increase of the intake air temperature as the engine warms up.