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Home >> Mercedes Benz >> 2021 >> A220 Base >> Repair and Diagnosis (Single Page) >> Electrical >> Charging Systems >> Electrical System, Equipment & Instruments - 177 Chassis (2 Of 4) >> Testing & Repair >> Remove/Install Active Brake Assist Electric Controller Unit >> Remove/Install Active Brake Assist Electric Controller Unit - AR54.21-P-0700MFB
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Remove/Install Active Brake Assist Electric Controller Unit - AR54.21-P-0700MFB

Model 177 

with code 258 (Collision warning system with active brake application FCW-Stop) 

with code 772 (AMG styling - Front spoiler, side skirts) 

Model 243 

with code 258 (Collision warning system with active brake application FCW-Stop) 

Fig 1: Active Brake Assist Electric Controller Unit Components Location - Model 177 With Code 258 With Code 772
G15492016REMOVINGINSTALLINGREFER TO SELF-DIAGNOSTIC SYSTEMSREFER TO SELF-DIAGNOSTIC SYSTEMSCourtesy of MERCEDES-BENZ USA
Notice  Notes on preventing damage to electronic components due to a magnetic tool   AH54.00-P-0002-01A
Notice  Information on preventing damage to electronic components due to electrostatic discharge   AH54.00-P-0001-01A
REMOVINGINSTALLING Remove/install     
1 Remove Mercedes star. Model 177
with code 258 (Collision warning system with active brake application FCW-Stop) with code 772 (AMG styling - Front spoiler, side skirts)
AR88.40-P-4053MFA
    Model 243
with code 258 (Collision warning system with active brake application FCW-Stop)
AR88.40-P-4053EQA
2 Unclip Active Brake Assist controller unit (A108) and release and disconnect electrical connector (1).    
3 Install in the reverse order.    
4.1 Commission Active Brake Assist controller unit (A108). If the Active Brake Assist controller unit (A108 has been replaced.  
REFER TO SELF-DIAGNOSTIC SYSTEMS     AD00.00-P-2000-06MFA
4.2 Perform calibration of Active Brake Assist controller unit (A108). If Active Brake Assist controller unit (A108) is reused.  
REFER TO SELF-DIAGNOSTIC SYSTEMS     AD00.00-P-2000-06MFA