An integrated test program runs off in the control unit when switching on ignition.
A further test program runs off at a road speed of 6 krn/h.
Testing at 6 km/h can be felt, since pump in hydraulic unit will run briefly.
Test cycle is repeated each time car moves off, if ignition had been turned off previously.
A shortcoming is shown by the ABS indicator lamp coming on. If the shortcoming is recognized,
ABS will be switched off. Operation of "conventional brake system" is guaranteed.
Wire Harness / Relays / Overvoltage Cutout
ABS has its own wire harness (No. 121}.
1 — Hydraulic unit plug
2 — Hydraulic unit ground
4 - Front speed sensors
7 — Central informer connection
8 — Steering mount ground
9 - Plug next to CEB
10 — Rear speed sensors
Power supply for the electronic control unit and pump motor relay comes via relay no. XVII on central electric board (arrow).
An overvoltage cutout is integrated in this relay and protects the electronic control unit against excessive voilage.
Wire harness has a 35-pin plug for connection on the electronic control unit
Relay (1) for solenoid valves and relay (2) for pump motor as well gs a 12-pin wire plug (3) are located under cover oi hydraulic unit. The plug socket has a diode for activation of ABS indicator lamp when multiple pin plug on electronic control unit is disconnected.
1 — Relay for solenoids
Connecting terminal for power supply (battery +) is located In engine compartment on bracket for hydraulic unit.
Wire (6) leads into the 12-pin plug.
4 - Connecting terminal
5 — Protective cap
Ground wire (9) for hydraulic unit is connected on wheel house wall
7 — Relay for solenoids
Speed sensor wires are connected on ABS wire harnesses with wire plugs
Wires have a gas-proof cover Precisely positioned rubber mounts and grommets are connected permanently on wire cover for routing of wires
Wires on rear wheel sensors are surrounded by an additional protective sleeve between the mounting points.
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