SI42.30-W-0003A | Service information: New ABS control units | 8.1.08 |
MODEL 374, 375.1 /3 /4, 940, 942, 943, 944, 950, 952, 953, 954, 957, 958.0 /2 /4, 970, 972, 974, 975, 976 as of 2.11.07 with CODE (B02) Brake system, antilock brake system (ABS)
General:
As part of ongoing technical development as of production period 11/2007 the previous ABS control units have been replaced by a new generation.
The new ABS control units offer additional functionalities such as flashing of software via the diagnostic interface.
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Features:
The control unit housing sizes are identical with the previous ABS control units. In the case of all new control unit variants the connection is made with two uniform 18-pin plugs (X1 and X2). The plugs are coded differently.
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Changed ALB function:
On vehicles up to 12 t permissible gross vehicle weight and with 3-channel ABS (without ASR) the new ABS control unit also takes over the ALB controller function (electronic brake force limitation).
Operating principle:
Via the evaluation of signals from the wheel speed sensors at the rear axle, wheel slip occurring is detected in good time during the brake application. The controlled ventilation of the corresponding brake cylinder reduces the brake pressure via the respective ABS solenoid valve.
The ALB controller can be dispensed with by the ALB controller function reproduced in the software.
A relay valve is fitted in place of the ALB controller.
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Advantages:
Discontinuity of ALB controller
Wear-free function - through a pure software solution
Maintenance free function - no adjustment operations on axle load-dependent brake linkage required.
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Supply of parts:
Three equipment variants are fitted in series production:
A 000 446 52 14
3-channel ABS, with/without ALB control
A 000 446 53 14
4-channel ABS, without ALB control, without ASR
A 000 446 54 14
4-channel ABS, without ALB control, with ASR
Only the equipment variant A 000 446 54 14 is supplied as a replacement part. This must be parameterized corresponding to the vehicle.
The new generation of ABS control units is not exchangeable with the previous ABS control units