esp mercedes
TRANSCRIPT
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ESPElectronic Stability Program
327 HO 05 ESP (WJB,GC) 02-26-04
Starting MY1996
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Objectives
At the end of this presentation, you should be able to:1. Explain the function of and purpose for ESP2. Describe the customer interface with ESP3. List the hydraulic and electronic components used for ESP4. Describe the ESP build up, holding and reduction control
modes
These technical training materials are current as of the date noted on the materials, and may be revised or updated without notice. Always check for revised or updated information. To help avoid personal injury to you or others, and to avoid damage to the vehicle on which you are working, you must always ref er to the latest Mercedes -Benz Technical Publication and follow all pertinent instructions when testing, diagnosing or making repair.Illustrations and descriptions in this training reference are based on preliminary information and may not correspond to the final US version vehicles. Refer to the official introduction manual and WIS when available. Copyright Mercedes-Benz USA, LLC, 2004WIS document numbers shown apply to WIS Version USA/CDN at date of writing.Reproduction by any means or by any information storage and retrieval system or translation in whole or part is not permitted without written authorization from Mercedes -Benz USA, LLC or it's successors. Published by Mercedes -Benz USA, LLC Printed in U. S.A.
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Contents
Purpose of ESP 4Driving with ESP 7ESP Electronic components 9Six ESP control modes 19Diagnosing Included ESP Functions 23Other Functions Related to ESP 24ESP block diagram 25
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Purpose of ESP
1. Prevent oversteer and understeer
2. Increase safety by providing stability
It does this by applying the appropriate brake(s)
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Advantages• Improved starting and acceleration capability
• Improved stability when:
• braking
• accelerating
• coasting
• cornering
• Shortens stopping distances in corners or on slippery surfaces
• Informs driver of slippery conditions
• ABS, ASR, EBR and ESP functions are combined in one control unit
• ABS, ASR, EBR and ESP basic components are combined in one hydraulic
unit
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Improved Braking Stability
Additional ESP system sensors provide for further enhanced braking stability.
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Driving with ESP
• Warning lamp flashes when ESP operates.
• The throttle control portion of ESP can be switched off with ESP OFF rocker switch.This will illuminate the warning lamp continuously.(may provide better traction in deep snow or when snow chains are mounted)
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Understeer and OversteerESP monitors the vehicle’s traction and handling, using sensors to
detect wheel speed, understeer and oversteer
Understeer Oversteer
Vehicle does not turn as sharply as desired. The vehicle seems to “plow” straight ahead. ESP will brake the inside rear wheel.
Vehicle turns in more sharply than desired. The rear of the vehicle swings outward. ESP will brake the outside front wheel.
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ESP Electronic Components
A1e17 ABS malfunction indicator lamp A1e41 ESP and ABS warning lamp A1p13 Multifunction displayA7/3n1 SBC control module B24/15 Lateral acceleration and yaw rate
sensor
N47-5 ESP, BAS and SPS control moduleN49 Steering angle sensor N72/1s1 ESP OFF switch X11/4 Diagnostic data link connector
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Steering Angle Sensor (N49)
•N80 - Steering column module
• A45 - SRS & horn clock spring
Signals the desired steering angle to ESP.ESP also recognizes cornering by monitoring input from the 2 front wheel speed sensors.
W220 shown
Front wheels must be straight when removing
and installing A45
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Early Version Steering Angle Sensor (N49)
a b
b - 8 apertures & barriers arranged in a specific pattern
a – 9 evenly spaced light emitting diodes (LEDs)
Must be re-initialized after the battery is disconnected, because N49 has a T.30 power connection.
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Late Version Steering Angle Sensor (N49)
W220 Shown
Screw
N80 = Steering column module
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Lateral Acceleration Sensor (B24/2)
Hall sensor
Magnetic mass
Produces a signal corresponding to the cornering forces.
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Yaw Rate Sensor (N64)
• Hollow cylinder vibrates by means of piezo elements
• Vibration patterns change due to rotary motion of vehicle
• Changes are used as a measure of Yaw rate of the vehicle
Measuring element:
Yaw: to turn around the vertical axis
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Combined Lateral Acceleration & Yaw Rate Sensor (B24/15)
Location shown on 211 chassis
When this component is replaced, adaptation must be performed. (refer to WIS: AD42.45-P-3000-2A)
Senses rotational speed of the vehicle about the vertical axis andthe lateral acceleration.
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Stop Lamp Switch (S9/1)
Two position switch: N.O. and N.C.
It is self-adjusting(NOTE: be sure to pull it all the way out before installing.)
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Stop Lamp Switch Service Note
• ESP fault codes C1200, C1201, C1202 may be set if the stop lamp
switch is misadjusted (implausible signal as compared to BAS
diaphragm travel sensor input)
• Check switch voltage supply
• Ensure correct switch part number is installed
• Adjust as per DTB 33/00 (5-26-00)
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CAN Communication
CAN communication with:• ME-SFI
(for torque reduction)• ETC - Electronic Transmission Control
(utilized for calculation of the ESP regulation)
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Six ESP Control Modes
1. Normal mode2. ABS mode (pressure holding and reduction)3. ASR mode (pressure build up, holding, and reduction)4. EBR mode (slight throttle opening)5. ESP “OFF” mode (switches off throttle control)6. ESP mode (pressure build up, holding, and reduction)
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y19
y22
y18
ESP Pressure Build Up
• BAS applies~5bar pressure
(Note: brake light suppression relay activated)
• y18,y19 close
• m1 activated• y22 opened• y6 closed
Example:Right front wheel requires braking
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ESP Pressure Holding
Example:Right front wheel
• y22 closed, preventing pressure build up
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ESP Pressure Reduction
Example:Right front wheel
• y18 is opened• Pressure returned to the master cylinder
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Diagnosing Included ESP Functions:
• ABS – Anti-lock Brake System• ASR – Acceleration Slip Regulation• EBR – Engine Braking Regulation• EBD – Electronic Brake Force Distribution • ETS – Electronic Traction System• ESP – Electronic Stability Program• BAS – Brake Assist System• 4ETS – 4MATIC
Pre-ESP systems
Post-ESP systems
To diagnose a function contained within ESP using DAS, you may have to begin at the ESP menu.
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Other Functions Related to ESP
• PML (SPS) – Speed Sensitive Steering• CAN communication• Electronic Accelerator (EA) intervention• Electronic Transmission Control (ETC)
intervention• Sensotronic Braking Circuit• Distance (DTR)• Airmatic, ABC, SAS suspension
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ESP Block Diagram
Front VSS
Terminal 61
Stop lamp switch
Data Link (X11/4)
CAN-C (VSS)
Rear VSS
Circuit 31Power
N47/
Return pump Relay K40/
Hydraulic control unit A7/
Parking Brake sw. ESP warning lamp
ESP MIL
ABS MIL
Lateral SensorSteering Angle
Pressure Sensor
Yaw Sensor