DescriptionThe electronic anti-lock brake system (BOSCH 5.7 ABS) governs braking pressure sent to the wheels and prevents loss of grip under all tyre and road surface conditions.The system is designed to be integrated with the braking system (using the same hydraulic fluid) without preventing the operation of the braking system if the operation of the ABS fails. Four sensors fitted to the four wheels inform the electronic control unit of wheel speed at every moment. In this way, they detect wheel lock, wheel slip and loss of grip.Under these conditions, the control unit sends specific instructions to solenoids that modulate hydraulic circuit pressure to eliminate lock and restore the car to within grip limits which allows optimum driveability and stopping distances.The sensors are the 'active' type, i.e. supplied by the control unit; they consist of a receiver that faces a magnetic coding device built into the hub bearing so that the signal is less influenced by electromagnetic interference and variations in temperature.The ABS control unit also controls brake force distribution of the rear axle in relation to the front axle, allowing the mechanical load proportioning device used previously to be dispensed with (EBD function: Electronic Brake Distribution).The control unit is equipped with a self-diagnostic function: when an error is detected in the ABS function the warning light comes on and the system is simultaneously deactivated; Under these conditions, the car brakes using only the conventional system. When the control unit detects an error which also affects the operation of the EBD logic, the 'ABS failure' warning light and the 'insufficient brake fluid level' and 'handbrake applied' warning light comes on.768
767Under these conditions, the rear brake distribution control is also deactivated: the customer must therefore drive very carefully to the first service centre.
For more details Characteristic of working principle 3340 A(B.S. ANTI-LOCK BRAKING SYSTEM .) . The ABS control unit computes true vehicle speed using values supplied by sensors on both drive wheels (the ABS control unit computes an average reading) and the true wheel circumference supplied by the body computer. This speed signal is then sent to nodes that require the information via the CAN network. The ABS control unit also generates a discrete signal that copies the vehicle speed information computed and transmitted via the CAN network. The control unit supply lines are protected by a special maxifuse located in the engine bay control unit. ignition-operated power supply from a special fuse in the underfacia control unit.
Functional description The ABS electronic control unit M50 is supplied (at pin 2 and 6) directly by the battery via a line protected by maxifuse F1, housed in the engine compartment junction unit B1. The ignition-operated supply (INT/A) reaches pin 23 from the line protected by the fuse F42 of under facia control unit B2 . The control unit is earthed via pins 1 and 5. The four sensors K70, K71, K75, K76 send wheel speed signals to pins 28-12, 15-16, 13-14 and 30-31 of M50 respectively. Brake pedal switch I30 sends an enablement signal to pin 14 of control unit M50 : the ABS cannot intervene unless the brake pedal is pressed. The switch I30 is supplied when the ignition is switched on (INT) from fuse F37 of junction unit B2 . Pin 37 of M50 emits a discrete speed signal for transmission to Body Computer M1 ; the same signal is also copied to the CAN network. Pins 24 and 40 of ABS control unit M50 connect to engine control unit M10, Body Computer M1 and instrument panel E50 to control the ABS warning light and - if the problem lies in the EBD function - the low brake fluid level and handbrake warning lights. Self-diagnostic data can be read by connecting to connector C of Body Computer M1- pin 1: it receives signals from pin 11 of the control unit M50 via the special diagnostic line. 3361166SeeE8010DIAGNOSTIC MULTIPLE CONNECTOR
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting21Disconnect the negative battery terminal.1. Remove the junction unit protective cover.192009560
5505A35
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting213363098-5530B56BATTERY DRIP TRAY COVER- R.R.Disconnect the battery negative terminal.3363361-7040A44facia lh side cover - r r1. Disconnect the front electrical connectors of the junction unitcomplete with body computer.2. Unscrew the retaining bolts.3. Remove from its seating the junction unit complete with bodycomputer.4. Disconnect the rear electrical connectors of the junction unitcomplete with body computer.2027438
5505A36
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting211. Separate the junction unit (1a) from the body computer (1b),by releasing the retaining lugs (1c).2027440
5505A41
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting213363098-5530B56BATTERY DRIP TRAY COVER- R.R.Disconnect the battery negative terminal.3363151-5580C18air bag module - r+r . 769- 4110A16 steering wheel - r r for replacement or checks forversions with airbag and manual gearbox with hydraulic selection . 1. Disconnect the electrical connectors (1a) and remove the controlunit (1b) from its seating.2027441
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting211. Disconnect the electrical connectors (1a) and (1b).2. Undo the fixing bolts (2a) and remove the door node (2b).2027444
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting213363098-5530B56BATTERY DRIP TRAY COVER- R.R.1. Release the clips and remove the protective cover for the uniton the battery.2. Undo the bolts (2a) and remove the battery fixing bracket (2b).3. Slacken the nut and disconnect the battery's negative terminal.2027495
5530B52
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting21Op. 5530B56 BATTERY DRIP TRAY COVER - R.R.3363098Op. 5530B10 BATTERY - R+R3363096- Disconnect the engine management unit electrical connections.Release the wiring from the retaining bands.1. Undo the rear fixing bolt (1a), release the front fastenings (1b) and place the engine compartment junction unit (1c) at the side.192008351
5530B56
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting211. Undo the fixing bolts (1a) and remove the battery cover (1b).2027502
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting213363098-5530B56BATTERY DRIP TRAY COVER- R.R.Disconnect the battery negative terminal.3363357-7040A26steering column trim - r+r1. Undo the bolts fixing the analogue instrument panel trim.2. Remove the trim under the instrument panel.3. Undo the upper bolts fixing the instrument panel to the dashboard;then partly release the panel.2027547
767 It is not possible toorder a single lock barrel or to order barrels using a single partcode. When ordering barrels, observe the special procedure illustrated 3363161See assembly5580E anti-theft device .
5520A18
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting213363098-5530B56BATTERY DRIP TRAY COVER- R.R.Disconnect the battery negative terminal.3363357-7040A26steering column trim - r+r1. Disconnect the electrical connectors of the ignition block (1a)and Cruise Control (1b).2. Release the retaining clips on the ignition switch contact block.2027470
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting21Op. 5530B56 BATTERY DRIP TRAY COVER - R.R.3363098Disconnect the negative battery terminal.- Disconnect the negative battery terminal.1. Undo the nut (1a), loosen the bolt (1b) and place the Selespeed fluid reservoir (1c) at the side.192008257
3340A13
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting21Op. 5530B56 BATTERY DRIP TRAY COVER - R.R.3363098Disconnect the negative battery terminal.1. Undo the nut (1a), loosen the bolt (1b) and place the Selespeed fluid reservoir (1c) at the side.192008263
<anchor>0</anchor><span>Removing</span><icon><imageid>20</imageid></icon>1Refitting21Position the vehicle on theramp.3363098-5530B56BATTERY DRIP TRAY COVER - R.R.Disconnect the battery negative terminal.1. Disconnect the rpm sensor electrical connection.2027134
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