ABS & Cruise Control - Diagnostic Tip

REF. NO.: MBNA 30/5, 42/9

TO:
OUR MERCEDES-BENZ PASSENGER CAR DEALERS

DATE: December 1992

SUBJECT:
MODELS 124, 126, 129, 140, AND 201 IDENTIFYING APPROPRIATE DIAGNOSTIC PROCEDURES FOR ABS AND CRUISE CONTROL

ANTI-LOCK BRAKE SYSTEM (ABS)

When diagnosing ABS related complaints, first determine if the subject vehicle is equipped with Acceleration Slip Regulation (ASR) before referring to the Diagnostic Manual.

Diagnostic testing of the ABS system on models 124.034/036, 129, and 140 equipped with ASR is covered in the ASR test, Section 5 of the Model 129 and 140 Diagnostic Manual, Chassis and Drivetrain. Do not refer to section 6, which is intended for diagnostic testing of the ABS system on models not equipped with ASR.

Please note that the recently distributed service microfiche titled Brakes II-ABS-ASR I for model 126 (fiche no. 07 102 2235 35) contains information concerning ASR not applicable to U.S. vehicles. Upon introduction in model year 1991, U.S. vehicles with ASR were equipped with ASR version 2 (ASR (1), which can be identified by a combined ABS/ASR hydraulic unit. ASR version I (ASR 1) which can be identified by separate ABS and ASR hydraulic units, does not apply to U.S. vehicles.

CRUISE CONTROL

When diagnosing cruise control related complaints, also determine if the subject vehicle is equipped with Acceleration Slip Regulation (ASR) before referring to the Diagnostic Manual or SMS.

Diagnostic testing of the cruise control system on models 124.034/036, 129, and 140 equipped with ASR is covered in the Electronic Accelerator test, Section 6 of the Model 129 and 140 Diagnostic Manual, Engines, Volume 3. Do not refor to section 7, which is intended for diagnostic testing of the ABS system on models 124.034 and 140 not equipped with ASR.





For additional information, please refer to the chart.

The chart gives a survey of where to find diagnostic procedures for ABS and cruise control depending whether or not the vehicle is equipped with ASR.