Signal Circuit Inspection

Ignition "ON" & Engine "ON".
Turn the steering wheel to the left or right.
Measure signal waveform between terminal "8,39,40" of the HECU harness connector and chassis ground.
Specification : Check the voltage range (HIGH : 2.9 ± 0.1V ~ 4.4 ± 0.1V, LOW : 1.2 ± 0.1V ~ 2.1 ± 0.1V) of the sensor signal in case of turning left, turning right, center position. If normal waveforms such as fig 1, 2, 3 are detected in each condition, It is normal.

Fig 1: Waveform Signal Graph
Courtesy of KIA MOTORS AMERICA, INC.

Fig 2: Measuring Signal Waveform Between Terminal "8,39,40" Of HECU Connector Ground
Courtesy of KIA MOTORS AMERICA, INC.
Is the measured signal waveform within specifications?
YES
- Substitute with a known-good HECU and check for proper operation. If problem is corrected, replace HECU and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
NO
- Check for open or short in steering angle sensor harness between terminal "3, 4, 5" of the steering angle sensor harness connector and terminal "39, 40, 8" of the HECU harness connector. Repair as necessary and then go to "VERIFICATION OF VEHICLE REPAIR " procedure.
- Go to "COMPONENT INSPECTION " procedure.