PRLog (Press Release) - Aug 16, 2011 - ABS Failures and Symptoms
ABS, from the German: Antiblockiersystem, is an automotive system no one thinks about until after it's done its job. From keeping our cars from sliding off the road during heavy braking in a rainstorm, to maintaining steering control during a stopping emergency. The anti-lock braking system in cars isn't something most like to do without. In emergency situations things can happen fast, and being able to maintain steering control is important.
The anti-lock brake system consists of the following components: • Hydraulic Control Unit (HCU). • Anti-lock brake control module. • Front anti-lock brake sensors / rear anti-lock brake sensors. (in 4 wheel ABS systems) Like any high temperature constant use electronic system, the ABS Control Module can begin to degrade. Automotive Scientific Inc. has identified the following failures or impending failures and what they mean.
A few of the issues in a degrading or failed ABS system are: No Communication False Wheel Speed Sensor Codes Open Circuit Codes Shorted Circuit Codes Constant Pump Activation No Pump Activation Valve Codes
No Communication: The Engine Control Unit (ECU) or Instrument Cluster or diagnostic scanner equipment can no longer communicate with the ABS module. The ABS / Traction / DSC Light etc… illuminate. What happens in most cases is the internal hardware of the ABS have failed, due to over-voltage issues or component degradation, many of the Anti-lock Brake systems have the control module in the engine bay, which can cause heat related premature failure of the internals.
False Wheel Speed Sensor Codes: The ABS module begins to active on soft stops or during regular driving; the ABS light comes on, a system scan shows "erratic" signals or "variations". What happens is that the system can no longer differentiate between a real wheel lockup and phantom signals during non-emergency situations. This situation can be dangerous as the abs system is meant to prevent wheel lock during high-pressure braking and emergency. Activation under normal conditions can be shocking and unexpected, distracting and increase stopping distance because of "pulsation" of brake calipers when they are lightly applied.
Open / Shorted Circuit Codes: The ABS syst oled technology on mobile phone em detects a problem in one or multiple Wheel Speed Sensor(WSS) Circuits. The WSS is how the module knows the speed of individual wheels, and is able to determine when the wheel "locks up". If diagnostics show the wires, harnesses and plugs my photo and wallpaper to be in good order. What happens is the module either looses the ability to power the sensors or can no-longer detect the "pulses" for the speeds. This causes the module to become blind to the wheel or wheels affected. Without this information the module is unable to properly judge how to pulse the wheels in an ABS situation, if the module activated and one or more wheels locked-up proper control of the vehicle could be lost.
Constant Pump Activation The pump runs continuously, the ABS light may or may not be on, diagnostics show Pump Relay type codes. What happens is the ABS module has lost the ability to turn the pump-on and off, over voltage or excessive heat causes the internal control systems to fail. Out of specification pumps can also over load a system or cause to much current draw which "burns" the control systems in the module. In a situation when the pump is constantly running, its possible the pump may burn out, or become excessively hot, which coupled with any amount of oil on the pump could cause a fire. The ABS fuse should be removed to protect the pump and vehicle from damage.
Valve Codes: The ABS control module is no longer able to control the activation of the hydraulic valves. The valves are electromagnetic couplers, which operate when voltage is applied. What happens is the modules ability to activate inlet and outlets valves becomes compromised; the rapid activation of the valves is what is responsible for the pulsation feeling on the brake peddle during ABS activation. When the system looses the ability to control hydraulic flow it is no longer able to release or apply pressure to the wheels during lock-up. This could cause wheels to remain locked or, reduce the clamp pressure of the pads.
Automotive Scientific Inc. Has identified the components that fail for each type of failure, and incorporate newest higher quality components to ensure proper operation for years to come.
We also have state of the art testing systems, that simulate the rigors of intense wheel lock and braking, our goal is the ensure long term operation of the rebuild services we perform.
View some of our popular EBCM Services.
VW/Audi http://www.autoecu.com/asi-AUDI-PASSA T-A4-A6-S4-ABS-ECU- ... GM Truck/SUV http://www.autoecu.com/asi-GM-CHEVY-SUV-PU-Tahoe-Escalad ... Ford Windstar http://www.autoecu.com/asi-FORD%20WINDSTAR%20ABS%20EBCM% ... Dodge Truck http://www.autoecu.com/asi-DODGE-PU-DURANGO-DAKOTA-ABS-ECM-ECU-RE BUILD-REPAIR.html
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