Anti-Lock Brake System

Anti-lock Brake System (ABS) And Anti-Lock Brake System With Electronic Differential Lock (ABS/EDL) ITT Mark 20 IE
General





ABS Layout
The ABS or ABS/EDL brake system is divided diagonally. Brake pedal pressure is assisted pneumatically by the vacuum brake booster.
Vehicles with ITT Mark 20 IE ABS do not have a mechanical brake pressure regulator. Specially matched software in the control module controls the rear axle brake pressure regulation.
Malfunctions of the ABS or ABS/EDL systems do not influence the brake system or the vacuum assistance. The conventional braking system remains functional even if the ABS is not operating.





The hydraulic part -a- and the control module part -b- form one component. Separating the two parts is only possible when the complete component has been removed from the vehicle.
New control modules (replacement parts) are not coded and must be coded after installation.

Distinguishing Features of ABS ITT Mark 20 IE And The ABS/EDL ITT Mark 20 IE





I-ABS-ITT Mark 20 IE
Dimension a = 100 mm (3.9 inch)





II-ABS/EDL-ITT Mark 20 IE
Dimension a = 130 mm (5.1 inch)

Notes For Repair Work On ABS, ABS/EDL

Warning!
^ Brake fluid is poisonous.

Note:
^ Before working on the ABS system, determine the cause of the malfunction using On Board Diagnostic (OBD) refer to Powertrain Management; Computers and Control Systems.
^ Before working on the ABS system, disconnect the battery ground strap. Obtain the radio code for vehicles with a coded radio.
^ Before doing any welding work with an electric welding unit, disconnect the ABS control module.
^ When working with brake fluid, observe the relevant safety precautions and notes.
^ If the brake hydraulic system had to be opened during the course of repair, bleed the brake system after completion of the repair.
^ During the final road test perform at least one controlled brake test where the brake pedal is felt to pulsate (ABS operation).
^ Absolute cleanliness is required when working on the ABS system. It is not permitted to use any products which contain mineral oil, greases, etc.
^ Thoroughly clean all connections and the adjacent areas before loosening. Do not use aggressive cleaning agents such as brake cleaner, gasoline, thinners or similar.
^ Place removed parts on a clean surface and cover them. Only use clean plastic covering or paper Do not use rags that may contain lint.
^ After separating the control module from the hydraulic unit, use the transportation protection for the valve dome.
^ Carefully cover or seal open components if repairs cannot be carried out immediately. Use the sealing plugs con rained in repair kit, Part No. 1 H0 693 311 A.
^ Do not use rags that may contain lint.
^ Only remove replacement parts from packaging immediately prior to installation.
^ Only use genuine packed parts.
^ When the system is open do not work with compressed air and do not move the vehicle.
^ Ensure that no brake fluid enters electrical connectors.