caddman6425
New Member
- Joined
- Dec 30, 2016
- Messages
- 2
- Reaction score
- 0
Hi all, this is my first post and I'm trying to build the circuit that is in the dealer scan tool to activate the automatic bleed on the ABS Controller. I'm working on my son's 2002 Tahoe and I really don't know if the brakes were spongey before I took it apart.
I bought this for him and we drove it from NC to OR and after we arrived in OR I discovered that the frame was bent, so I replace it. I knew about the automatic bleed on the controlled and I thought that my Snap-On scanner would do the trick, but I was totally mistaken. I can't afford to buy a new scanner so I have done the trick of the lonely gravel road, on a dyno, but to no avail. I've rebuilt all calipers, replaced the MC, and totally flushed the PS.
I started researching the operation of the WSS and the information that is in my AllData, I think is miss leading, so I thought that I'd might ask some younger tech my questions.
AllData says:
Wheel Speed Sensors (WSS) - As the front wheels spin, toothed rings located at each wheel hub interrupt magnetic fields in the wheel speed sensors. This causes each wheel speed sensor to generate an AC signal. The EBCM uses these AC signals to calculate the wheel speed. The wheel speed sensors are serviceable only as part of the wheel hub and bearing assemblies. Any imperfections in the toothed ring, such as a missing or damaged tooth, can cause an inaccurate WSS signal.
Vehicle Speed Sensor (VSS) - The input signal for rear wheel speed originates at the VSS. The Powertrain Control Module (PCM) receives rear wheel speed input from the information to the EBCM.
AC signal??? Isn't it a DC square wave? This is the first in a bunch of question, unless some one has a schematic of this circuit I'm trying to build?
I bought this for him and we drove it from NC to OR and after we arrived in OR I discovered that the frame was bent, so I replace it. I knew about the automatic bleed on the controlled and I thought that my Snap-On scanner would do the trick, but I was totally mistaken. I can't afford to buy a new scanner so I have done the trick of the lonely gravel road, on a dyno, but to no avail. I've rebuilt all calipers, replaced the MC, and totally flushed the PS.
I started researching the operation of the WSS and the information that is in my AllData, I think is miss leading, so I thought that I'd might ask some younger tech my questions.
AllData says:
Wheel Speed Sensors (WSS) - As the front wheels spin, toothed rings located at each wheel hub interrupt magnetic fields in the wheel speed sensors. This causes each wheel speed sensor to generate an AC signal. The EBCM uses these AC signals to calculate the wheel speed. The wheel speed sensors are serviceable only as part of the wheel hub and bearing assemblies. Any imperfections in the toothed ring, such as a missing or damaged tooth, can cause an inaccurate WSS signal.
Vehicle Speed Sensor (VSS) - The input signal for rear wheel speed originates at the VSS. The Powertrain Control Module (PCM) receives rear wheel speed input from the information to the EBCM.
AC signal??? Isn't it a DC square wave? This is the first in a bunch of question, unless some one has a schematic of this circuit I'm trying to build?
