ABS and Handbrake Lights Both On

[dr. d]

I'm surprised nobody mentioned using an oscilloscope to observe/monitor thebehavior of the wheel speed sensors. Physically moving, unplugging and reinstalling may mask the symptoms temporarily. Wika nga, do not contaminate the evidence. True over time the magnetic tip of the wheel speed sensor picks up ferrous dust or debris that makes the speed sensor "dirty" with garbled signal which in turn "confuses" the EBCM and by default turn the brake warning light ON. In case of sensor tip debris, most of the time, if accessible, can be cleaned and reinstalled, DTCs erased and send the car on it's merry way.

nice to have, but "who knows how to use oscilloscopes nowadays?"
... from the generation who would replace spark plugs rather than clean and re-gap them...

[jick.cejoco]

A digital storage oscilloscope is not a nice to have but a must have for a reputable technician. Similar to the medical field, a hospital must at least have an X ray machine. You can not advice or recommend to a patient what to do if you are limited on informational or diagnostic equipment.

[oj88]

nice to have, but "who knows how to use oscilloscopes nowadays?"

I do. But it doesn't mean I'm confident enough to poke at the ECM/PCM/ABS module pins. lol

[jick.cejoco]

The subject vehicle in question is a typical four channel ABS/traction controlled system that uses two wire sensors( per channel). You can set your DSO in auto mode(voltage for Y axis and time/frequency for X axis) and adjust either once you capture the waveform. There are tutorials on YouTube on the use of DSO. There are also tutorials from aeswave.com.