ABS/Electronic Stabilization Program, Bosch 8.1 Component Overview
ABS/Electronic Stabilization Program, Bosch 8.1 Component Overview
The Bosch ESP 8.1 has the following functions:
• ABS - Anti-lock braking system
• ASR - Anti-slip regulation
• EBD - Electronic brake pressure distribution
• EDL - Electronic differential lock
• ESP - Electronic stabilization program
• FBS - Fading brake support
• HBA - Hydraulic brake assist
• MSR - Engine drag torque regulation
• Emergency braking signal
• Brake disc cleaning
• Trailer stabilization
The brake system is distributed diagonally. The vacuum brake servo unit boosts the brakes pneumatically.
ABS disturbances do not affect the brake system and the booster. Conventional brake system stays operative even without ABS. A change in braking behavior should be checked. When the ABS warning lamp comes on the rear wheels can lock-up early when braking!
Malfunction sources are reduced by direct connection of components named. The components are replaced instead of repaired.
1 - Right rear ABS wheel speed sensor G44
• Removing and Installing, refer to => [ Rear ABS Wheel Speed Sensors ] Rear ABS Wheel Speed Sensors
• Can be tested in "Guided Fault Finding" with the vehicle diagnosis, testing and information system (VAS 5051B) or (VAS 5052)
2 - Left rear ABS wheel speed sensor G46
• Removing and Installing, refer to => [ Rear ABS Wheel Speed Sensors ] Rear ABS Wheel Speed Sensors
3 - ESP Sensor Unit (G419)
• Component location: Under the left seat
• Removing and Installing, refer to => [ ESP Sensor Unit ] ESP Sensor Unit
• 9 Nm
• Combined Transverse Acceleration Sensor (G200), Rotation Rate Sensor (G202) and Longitudinal Acceleration Sensor (G251).
• Can be tested in "Guided Fault Finding" with the vehicle diagnosis, testing and information system (VAS 5051B) or (VAS 5052)
• Observe installation instructions
• Check arrow in the direction of travel when installing
4 - Brake lamp sensor
• Component location: On brake pedal
• Removing and Installing, refer to => [ Brake Lamp Sensor ] Service and Repair
• can be tested in "Guided Fault Finding" with the vehicle diagnosis, testing and information system (VAS 5051B) or (VAS 5052)
Cannot be reused after removal.
5 - Brake pedal
• With bracket for the brake lamp sensor
• Removing and Installing, with Automatic Transmission, refer to => [ Brake Pedal with Automatic Transmission ] Brake Pedal With Automatic Transmission
6 - Electro-Mechanical Parking Brake Indicator Lamp
• Located in the tachometer.
• Lights up when the parking brake is engaged and the ignition is switched on,
• Lights up for approximately 30 seconds when the parking brake is engaged and the ignition is switched off
• Blinks after engaging the parking brake if the brake pressure is not sufficient to prevent the vehicle from rolling.
• The indicator light must go out when the parking brake is released.
7 - Brake system warning lamp
• Located in the tachometer.
• Lights up with the ABS indicator lamp when the ABS system malfunctions
• Blinks when brake fluid is too low
• Blinks when there is a brake system malfunction
The malfunction is indicated more precisely when the "SET button" in the instrument cluster is pressed.
8 - ABS warning lamp
The indicator lamp monitors the ABS and the Electronic Differential Lock (EDL).
• Component location: In tachometer
• Lights up for several seconds when ignition is switched on and goes out after an automatic ABS system self-check if there are no malfunctions in the ABS system.
• There is an ABS malfunction if the indicator light:
• Does not light up when ignition is switched on,
• Does not go out after a few seconds,
• Lights up while driving.
• The vehicle can be stopped with the standard brake system. However, a change in braking behavior should be checked.
The Electronic Differential Lock (EDL) and ABS work together. The ABS indicator light lights up when the EDL malfunctions.
9 - ABS/ESP Control Lamp
• Component location: In the tachometer
• Blinks when driving if ESP/ASR engages regularly.
• Comes on when ignition is switched on and goes out after a short self-check.
• Comes on if there is an ESP system malfunction.
• Comes on if there is an ABS system malfunction because ESP and ABS work together.
• Comes on when ESP/ASR is switched off.
• Comes on during sensor programming if:
• Battery was disconnected and connected,
• Vehicle was started with jump start,
• Battery is too weak.
• After the sensor programming procedure, the ESP light goes out after driving a short distance.
10 - Left front ABS wheel speed sensor G47
• Removing and Installing, refer to => [ Front ABS Wheel Speed Sensors ] Front ABS Wheel Speed Sensors
• Can be tested in "Guided Fault Finding" with the vehicle diagnosis, testing and information system (VAS 5051B) or (VAS 5052)
11 - ABS hydraulic unit with ABS control module J104
• Removing and Installing, refer to => [ ABS Hydraulic Unit N55 with ABS Control Module ] Service and Repair
12 - Return ring
• Installation location: Installed on the steering column with the slip ring, refer to Description and Operation
• Removing and Installing, refer to => [ Steering Angle Sensor G85 ] Service and Repair
13 - Steering Angle Sensor (G85)
• Component location: Installed in coil ring with slip ring on steering column, refer to Description and Operation
• Removing and Installing, refer to => [ Steering Angle Sensor G85 ] Service and Repair
• Perform zero adjustment
Vehicle diagnosis, testing and information system (VAS 5051B) or (VAS 5052)
14 - Right front ABS wheel speed sensor G45
• Removing and Installing, refer to => [ Front ABS Wheel Speed Sensors ] Front ABS Wheel Speed Sensors
15 - ASR/ESP Button (E256)
• The installation location depends on the model, refer to => [ ASR/ESP Switch ] Locations
• Switches ESP/ASR off and on
16 - Audi Hold Assist pressure switch
• Located in the center console
• Function, refer to => [ Audi Hold Assist ] Description and Operation
• Removing and Installing, refer to => [ Audi Hold Assist Switch ] Service and Repair
17 - Parking Brake Pressure Switch (F234)
• Located in the center console
• Removing and Installing, refer to => [ Electro-Mechanical Parking Brake Switch ] Electro-Mechanical Parking Brake Switch
18 - Data Link Connector (DLC)
• Component location: Cover in driver footwell
19 - Roof rack recognition sensor (G625)
• The roof rack recognition sensor (G625) is always installed in the left roof railing.
• The sensor cannot be replaced by itself. It is part of the left roof railing.
• Removing and installing, refer to => [ Roof Rack Recognition Sensor ] Roof Rack Recognition Sensor
