2002 Hyundai Sante Fe ABS wheel speed sensor fault codes C1202 C1203 C1208 C1211

2002 Hyundai Sante Fe ABS wheel speed sensor fault codes C1202 C1203 C1208 C1211

ABS and traction control lights were on. Fault codes wer stored in ABS control module: C1202 C1203 C1208 C1211

2011-01-20 17.15.46
2011-01-20 17.15.56

Shop owner stated if he cleared codes they would return immediately. Although when driving the vehicle wheel speeds displayed correctly on scan tool. I drilled down the data stream to only the wheel speed sensors, then drove the vehicle. I noticed every time I started the RF sensor reading would spike to a maximum reading of 155 mph. I apologize for not having a screen shot of the graph. I could not snap one while I was driving. I do have video of the spike below taken while the vehicle was on a lift.

The shop owner asked why he would have 4 codes if only one sensor was faulty. I said the spike must be caused by a short and the ABS module is reacting as it is programmed to do. Now it’s time to prove that theory.

I got access to the RF WSS
2011-01-20 17.14.50
Backprobed it and used his graphing multi meter to view the waveform.
The wiring diagram showed two wires. This could be either a hall effect sensor or an voltage generating inductance sensor. I went with the latter knowing the make fairly well.
2011-01-20 17.14.14

The pattern showed the spike I was expecting.
2011-01-20 17.06.51

When I slowed the wheel down you can see why it is causing the high speed spike. The short voltage spikes higher than the voltage generated at the normal speed when starting out.
2011-01-20 17.07.23

To back up my theory of this being the only faulty sensor; I unplugged it, cleared fault codes and reread the codes to see what returned.

2011-01-20 17.16.24
2011-01-20 17.16.43
Only a code for RF WSS returned. This would be the only faulty sensor. The shop ordered one and it did indeed remedy all fault codes.

Here is an example of what a known good WSS on this vehicle looks like on the GMM. For reference:
2011-01-20 17.12.17