Tell me about my "Traction Control"
#11
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Originally Posted by Echo SSEI
Originally Posted by BillBoost37
Give the front two wheel speed connectors and wiring a good check over since the trans was recently out of the car.
#13
DINOSAURUS BOOSTUS
Expert Gearhead
Did you disconnect and double check the pins to make sure they didn't get bent when going back together. And how about the wiring feeding them. Most likely your cradle was removed and it'* possible wires got molested.
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Originally Posted by BillBoost37
Did you disconnect and double check the pins to make sure they didn't get bent when going back together. And how about the wiring feeding them. Most likely your cradle was removed and it'* possible wires got molested.
#15
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I've been through this extensively on the Zilla.
Both systems are related, but don't always use the same PORTIONS of the same components.
TRACTION:
All 4 wheel speed sensors are used. The front spinning tires are determined to be spinning by the comparison to the rear speed sensors which cannot. The rear is the reference. If traction loss is detected, the PMV (pressure modulator valve) assembly opens small solonoids to the front calipers, allowing pressurized brake fluid from the PMV pump assembly (to whichever wheel is spinning) applying braking force to make them only spin a certain percentage faster than the rear (this is because when in a left turn, the RF is normally travelling faster). Typical failures can be (in order of likelyhood):
1. Wheel speed sensor. Corrosion, wiring, or sensor (hub).
2. PMV. Very expensive. Learn to live without traction like me. This is where the little solonoids fail from old corrosive brake fluid, and they can no longer open.
3. EBCM. Electronic brake control module. This is the brain. Also very expensive, but in all my time here, I've only seen one that PROBABLY failed.
ABS:
Works nearly the opposite as traction. While this isn't your problem, just understand that it PULSES the calipers OFF based on the wheel speed at all 4 wheels, getting an input from the VSS (vehicle speed sensor). If the vehicle is still moving (slowing down) and it detects the right rear is not moving, it will remove braking from that one in pulses to allow it to continue to spin and brake, preventing a skid.
********************************************
This is information is in GENERAL for the 92-95 cars that don't use torque management to help contol traction.
********************************************
John, some basic checks are in order for your WSS connections and wires (remember my accessory belt shredding at Woodburn back in 04? It ripped out my RF wss wiring), and the FSM should have some BASIC WSS functions you can check with a meter.
Both systems are related, but don't always use the same PORTIONS of the same components.
TRACTION:
All 4 wheel speed sensors are used. The front spinning tires are determined to be spinning by the comparison to the rear speed sensors which cannot. The rear is the reference. If traction loss is detected, the PMV (pressure modulator valve) assembly opens small solonoids to the front calipers, allowing pressurized brake fluid from the PMV pump assembly (to whichever wheel is spinning) applying braking force to make them only spin a certain percentage faster than the rear (this is because when in a left turn, the RF is normally travelling faster). Typical failures can be (in order of likelyhood):
1. Wheel speed sensor. Corrosion, wiring, or sensor (hub).
2. PMV. Very expensive. Learn to live without traction like me. This is where the little solonoids fail from old corrosive brake fluid, and they can no longer open.
3. EBCM. Electronic brake control module. This is the brain. Also very expensive, but in all my time here, I've only seen one that PROBABLY failed.
ABS:
Works nearly the opposite as traction. While this isn't your problem, just understand that it PULSES the calipers OFF based on the wheel speed at all 4 wheels, getting an input from the VSS (vehicle speed sensor). If the vehicle is still moving (slowing down) and it detects the right rear is not moving, it will remove braking from that one in pulses to allow it to continue to spin and brake, preventing a skid.
********************************************
This is information is in GENERAL for the 92-95 cars that don't use torque management to help contol traction.
********************************************
John, some basic checks are in order for your WSS connections and wires (remember my accessory belt shredding at Woodburn back in 04? It ripped out my RF wss wiring), and the FSM should have some BASIC WSS functions you can check with a meter.
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