2001 Mercedes-Benz ML430

ODI opened the investigation based on reports that the subject vehicle brake lamp switch (switch) failure caused 1) inoperative brake lamps (stay on or fail to illuminate), and/or 2) shift interlock failure (shifter locked in park), and/or 3) the cruise control to fail to cancel with brake application.Consumers also reported the illumination of a warning lamp on the instrument panel.The switch contains three sets of electrical contacts and a (normally extended) spring loaded plunger that actuates the contacts as it moves.As installed in the vehicle, the plunger contacts the brake pedal arm and is pushed into the switch; as the driver applies the pedal the plunger extends.One set of contacts (BLS) operates the stop lamps, a second set (EWM) controls the shift interlock system, and a third set (BS) is used by an on-board diagnostic (OBD) system to monitor switch operation.The cruise control monitors the BLS signal to determine when the brake is applied, the primary way the system is disabled when set.The relative timing of contact actuation in response to plunger movement allows the OBD system to detect a switch fault.When a fault is detected a malfunction indication lamp (MIL) is illuminated (driver alert), a diagnostic trouble code (DTC) is stored (for the service technician), and cruise control operation is inhibited (as a failsafe).In its response to ODI's January 2011 information request letter, MB explained its assessment of switch failures which was based primarily on evaluation of field return failures.MB identified both 1) electrical contact and 2) mechanical switch failure mechanisms.According to MB's analysis, electrical contact failure is the predominate failure type and the failure consequence depends on which contact fails.For instance MB claims that BLS contact failures are momentary in nature and do not affect brake light operation but are nonetheless detected by the OBD system, resulting in a DTC and subsequent replacement.Electrical contact failures of the BS and EWM contacts result in a DTC also, and EWM contact failures result in the shifter being stuck in the park (which can be overridden by the consumer).Accordingly MB maintains that electrical contact failures of the switch have no safety consequence since the brake lamps remain operational and the cruise control is always disabled.MB determined that mechanical failures of the switch, which are rare in their assessment, can result from internal wear and/or increased switch operating temperatures.High temperatures occur due to overheating of the BLS contacts and can cause the internal plastic components to melt.In one scenario overheated BLS contacts may melt to the extended plunger and are damaged when the brake pedal is released resulting in the brake lights staying on.In another scenario the increased temperatures and/or internal wear can cause the plunger to stick in the fully depressed position.In this case the cruise may not cancel when the brake is applied and the driver may have to use high brake pedal forces or other means (shifting to neutral or using the cruise master switch) to disengage the cruise.Additionally the vacuum assist can be depleted if the driver pumps the brakes resulting in reduced braking effectiveness and even higher pedal forces.In its March 31, 2011 defect notification, MB stated that to remediate the potential need for excessive brake force it would conduct a safety recall (11V-208) to replace the switch with a more robustly designed component.The recall includes 136,751 model year 2000 - 2002 M-Class and model year 2000 - 2004 M-Class AMG vehicles.Owner notification letters will be mailed

ANALYSIS OF COMPLAINTS TO ODI AND MERCEDES AND WARRANTY CLAIM DATA SUBMITTED BY MERCEDES INDICATES THAT THE ALLEGED DEFECT HAS OCCURRED AT A LOW RATE (36.5 COMPLAINTS PER 100,000 VEHICLES AND 0.29 PERCENT WARRANTY CLAIM RATE), WITH NO DISCERNABLE DEFECT TREND INDICATING THAT THE RATE OF CHAFING RELATED BRAKE LINE FAILURES IS INCREASING.THERE HAVE BEEN NO NEW COMPLAINTS SINCE JANUARY 2009.WHEN THE ANALYSIS IS LIMITED TO INCIDENTS OF BRAKE LINE LEAKAGE THAT RESULTED IN ALLEGATIONS OF REDUCED BRAKE EFFECTIVENESS, THE RATE DROPS EVEN FURTHER (22.3 COMPLAINTS PER 100,000 VEHICLES AND 0.04 PERCENT WARRANTY CLAIM RATE). MERCEDES PROVIDED DATA SHOWING THAT IN THE RARE INSTANCES WHEN CHAFING DID PROGRESS TO BRAKE LINE LEAKAGE THE DRIVER WOULD BE IMMEDIATELY ALERTED TO A PROBLEM BY ILLUMINATION OF THE BRIGHT YELLOW ESP/BAS WARNING LAMP AND CHANGES IN BRAKE PEDAL FEEL.CONTINUED OPERATION WITH A LEAKING BRAKE LINE WOULD RESULT IN ILLUMINATION OF THE BRIGHT RED BRAKE WARNING LAMP AND AN AUDIBLE CHIME DUE TO LOW MASTER CYLINDER RESERVOIR LEVEL. CONTINUED OPERATION WITH THE BRAKE WARNING LAMP ILLUMINATED WOULD ULTIMATELY DRAIN THE RESERVOIR FOR THE AFFECTED CIRCUIT, RESULTING IN LOSS OF THE CIRCUIT AND AN APPROXIMATELY 80% INCREASE IN STOPPING DISTANCES. SURVEYS CONDUCTED BY ODI AND VRTC INDICATE THAT ROUTING ANOMALIES MAY BE MORE COMMON THAN THE COMPLAINT AND WARRANTY DATA SUGGEST FOR THE SUBJECT LINE BUNDLE, WITH LINE CONTACT OR OTHER ROUTING ANOMALY NOTED IN 13 OF 51 VEHICLES SURVEYED BY ODI AND VRTC (25.5%).WHILE EVIDENCE OF CONTACT BETWEEN THE FUEL LINE AND SUBJECT BRAKE IN A PARTICULAR VEHICLE IS NOT NECESSARILY PREDICTIVE OF EVENTUAL LINE FAILURE/LEAKAGE, SIGNIFICANT CHAFING WEAR WAS NOTED IN TWO SURVEY VEHICLES (3.9%).TO ADDRESS CONCERNS WITH LINE ROUTING AND ENSURE THAT LINES WITH EVIDENT CHAFING DO NOT PROGRESS TO A LEAK CONDITION, MERCEDES WILL CONDUCT AN OWNER NOTIFICATION PROGRAM INSTRUCTING OWNERS TO BRING THE VEHICLES TO A DEALER FOR A FREE INSPECTION AND REPAIR.LINES THAT DO NOT HAVE A SPACER (RUBBER GROMMET OR OMEGA-CLIP) BETWEEN THE SUBJECT FUEL AND BRAKE LINES WILL HAVE AN OMEGA-CLIP SPACER INSTALLED TO ENSURE ADEQUATE CLEARANCE BETWEEN THE LINES.BRAKE LINES WITH CHAFE MARKS WILL BE REPLACED. ACCORDINGLY, THIS INVESTIGATION HAS BEEN CLOSED. THE CLOSING OF THIS INVESTIGATION DOES NOT CONSTITUTE A FINDING BY NHTSA THAT A SAFETY-RELATED DEFECT DOES NOT EXIST. THE AGENCY WILL CONTINUE TO MONITOR COMPLAINTS AND OTHER INFORMATION RELATING TO THE ALLEGED DEFECT IN THE SUBJECT VEHICLES AND TAKE FURTHER ACTION IN THE FUTURE IF WARRANTED. FOR ADDITIONAL INFORMATION REGARDING THIS ENGINEERING ANALYSIS REFER TO THE EA08-009 CLOSING REPORT.

ODI OPENED PE07-007 AFTER RECEIVING 4 COMPLAINTS WITHIN A 6 WEEK PERIOD ALLEGING INCIDENTS OF UNCOMMANDED BRAKE APPLICATION IN MODEL YEAR (MY) 2000 THROUGH 2001 MERCEDES M CLASS SPORT UTILITY VEHICLES.INFORMATION CONTAINED IN THE REPORTS OR GATHERED IN SUBSEQUENT CONSUMER INTERVIEWS INDICATED THAT THE INCIDENTS WERE CAUSED BY FAULTS IN THE ELECTRONIC STABILITY PROGRAM (ESP) SYSTEM WHICH WERE REPAIRED BY REPLACING THE YAW RATE SENSORS.ALTHOUGH THE SAME YAW RATE SENSOR IS USED IN APPROXIMATELY 800,000 OTHER MERCEDES M-CLASS, C-CLASS AND SLK MODELS, TO DATE THERE HAS BEEN ONLY ONE RELATED COMPLAINT TO ODI IN THOSE VEHICLES. DURING THIS INVESTIGATION MERCEDES BENZ PROVIDED ODI WITH 327 COMPLAINTS RELATED TO THE ESP SYSTEM IN THE MY 2000 THROUGH 2001 M CLASS VEHICLES.SEVEN OF THE COMPLAINTS SUBMITTED BY MERCEDES ALLEGED INCIDENTS OF UNCOMMANDED BRAKE ACTIVATION WHILE DRIVING, WITH TWO OF THESE INVOLVING VEHICLES IDENTIFIED IN THE ODI COMPLAINTS.NONE OF THE INCIDENTS RESULTED IN CRASH OR INJURY.HOWEVER, THE OWNERS DID EXPRESS SAFETY CONCERNS DUE TO THE SUDDEN, UNEXPECTED CHANGE IN VEHICLE SPEED AND DIRECTION. ON MAY 10, 2007 MERCEDES BENZ MET WITH NHTSA TO PROVIDE A TECHNICAL PRESENTATION AND CONDUCT A DRIVING DEMONSTRATION OF THE ESP SYSTEM PERFORMANCE WITH SIMULATED ELECTRICAL FAULTS IN THE YAW RATE SENSOR.MERCEDES SHOWED THAT THE ESP SYSTEM IS PROGRAMMED TO DIAGNOSE ELECTRICAL FAULTS AND THAT BRAKE APPLICATIONS RESULTING FROM YAW RATE SENSOR ELECTRICAL FAULTS ARE VERY SHORT IN DURATION (0.3 SECONDS OR LESS) AND DO NOT AFFECT VEHICLE CONTROL OR STABILITY. NINE OF THE CONSUMER COMPLAINTS TO ODI AND MERCEDES ALLEGED BRAKE ACTIVATIONS LONGER THAN 0.3 SECONDS, WITH SEVERAL ALLEGING THAT THE INCIDENT LASTED UNTIL THE VEHICLE CAME TO A STOP.A COMPLAINT VEHICLE THAT ALLEGED MULTIPLE INCIDENTS WAS EVALUATED BY ODI AT THE VEHICLE RESEARCH AND TEST CENTER (VRTC) IN EAST LIBERTY, OHIO.VRTC WAS UNABLE TO DUPLICATE THE CONDITION.DUE TO THE LOW COMPLAINT RATE AND ONLY ONE NEW COMPLAINT TO ODI OR MERCEDES SINCE JANUARY 2007, THIS INVESTIGATION HAS BEEN CLOSED.ODI WILL CONTINUE TO MONITOR COMPLAINTS IN THE SUBJECT VEHICLES AND OTHER MERCEDES PRODUCTS USING THE SAME YAW RATE SENSOR AND MERCEDES WILL PROVIDE UPDATES ON FIELD EXPERIENCE (COMPLAINTS, FIELD REPORTS AND WARRANTY CLAIMS) THROUGH THE END OF 2007.

Was driving 50 miles per hour when the car slammed on the brakes, nearly getting me rear ended. The throttle would not respond until the car was doing maybe5 miles per hour - on an interstate! The BAS/ESP light was on solid. I got onto an off ramp, called the dealer, was told it could be several causes, drove home carefully, and took it to the dealer. The dealer found nothing. Several times since, the car was being driven at speeds in the 20-30 miles per hour range, and the system would slam on the brakes and pull hard to the left. I could smell the brake dust in the car. Other times, it will ALMOST engage (ESP light flashes as well) then backs off.

NHTSA ID

11637080

Incident

Aug 24, 2022

RE: 2001 MB ML430 ELECTRONIC BRAKING SENSOR THE FRONT PASSENGER BRAKE INITIALLY LOCKED UP AT LOW SPEED UPON ACCELERATION. AFTER STOPPING AND TURNING THE VEHICLE OFF AND BACK ON THE SYSTEM WAS BACK TO NORMAL. THEN ONE DAY I WAS TRAVELING AT NEAR 70 MPH IN THE PASSING LANE OF AN INTERSTATE HIGHWAY WHEN THE FRONT DRIVER BRAKE LOCKED UP AND BRAKE TIRE SMOKE BILLOWED FROM MY VEHICLE WHICH CAUSED TRAFFIC BEHIND ME TO SWERVE AND BRAKE BEHIND AND ON THE SIDE OF ME. I PROCEEDED TO PULL OFF ONTO THE SHOULDER OF THE HIGHWAY AND TURNED MY VEHICLE OFF AND BACK ON, AFTER WHICH MY VEHICLE OPERATED NORMALLY. I PROCEEDED TO DO AN ONLINE SEARCH AND LEARNED THAT THIS WAS A COMMON SORT OF PROBLEM FOR THIS MODEL.. PARTICULARLY AT LOW SPEEDS. IN MY CASE IT HAPPENED AT LOW SPEEDS AND THEN THE ONE TIME AT 70 MPH. I LEARNED THAT THE YAW SENSOR WHICH IS PART OF THE ABS SYSTEM WAS COMMONLY REPORTED AS THE LIKELY CAUSE OF THE PROBLEM.. I PROCEEDED TO DISCONNECT THE YAW SENSOR AND HAVE HAD NO FURTHER PROBLEMS. I AM FORTUNATE THAT IT WAS NOT A RAINY DAY, OTHERWISE THE RESULTS MAY HAVE BEEN CATASTROPHIC WITH SO MANY VEHICLES BEHIND ME AND TRAVELING AT SUCH A HIGH SPEED. THEYAW SENSOR MB PART # IS A 002 542 94 18 Q01 SYSTRON DONNER INERTIA DIVISION USA

NHTSA ID

11035778

Incident

Oct 14, 2017

Mileage

125,000 mi

TWICE NOW WHILE DRIVING AND GOING OVER MINOR BUMPS (DOTS ON THE ROAD TO WARN OF CROSSWALKS AND A DRIVEWAY ENTRANCE CURB) THE BAS/ESP AND HAZARD LIGHTS HAVE COME ON AND THE CAR HAS AUTOMATICALLY APPLIED VIOLENT BREAKING THAT TOOK CONTROL OF THE DIRECTION THE CAR WAS HEADING. THIS BREAKING CONTINUED UNTIL THE VEHICLE CAME TO A COMPLETE STOP. BOTH TIMES THE CAR WAS GOING LESS THAN 20 MPH, BUT CONTROL OF THE CAR WAS LIMITED DURING THE EVENT. AT FREEWAY SPEEDS, IT WOULD BE VERY LIKELY TO CAUSE AN ACCIDENT. BAS/ESP LIGHT TURNS OFF AFTER THE CAR IS TURNED OFF.

NHTSA ID

11022910

Incident

Sep 10, 2017

Mileage

170,000 mi

VEHICLE'S FRONT WHEEL BRAKES BY ITSELF WHILE DRIVING AND THE EPS WARNING LIGHT COMES ON AFTERWARDS. EXTREMELY DANGEROUS IN HIGHWAY DRIVING. HAD THE BRAKES CHECKED, BUT NOTHING WRONG. ONLINE COMPLAINTS SUGGESTS A FAILURE IN YAW RATE SENSOR.

NHTSA ID

11005565

Incident

May 7, 2017

Mileage

105,000 mi

I WAS DRIVING ON THE HIGHWAY, GOING ABOUT 60 MPH, AND THE CAR SUDDENLY STARTED APPLYING THE BRAKES ON ITS OWN. NEARLY GOT ME INTO AN ACCIDENT. I WAS ABLE TO GET OVER TO THE SHOULDER LUCKILY. I HAD MY TODDLER IN THE CAR AND IT WAS A VERY SCARY THING. WHEN THE BRAKES STARTED ENGAGING BY ITSELF, A YELLOW TRIANGLE WARNING LIGHT DISPLAYED ON THE DASH FOLLOWED BY THE BAS/ESP LIGHT AFTER THE VEHICLE CAME TO A COMPLETE STOP. I HAVE SEEN OTHERS THAT HAVE HAD THIS VERY SAME ISSUE AND SEEMS TO BE THE YAW RATE SENSOR. I AM SHOCKED THIS HASN'T BEEN RECALLED WITH ALL THE ISSUES I'VE READ ON THIS. I BARELY JUST BOUGHT THE CAR AND IT'S ALREADY NOT DRIVABLE. VERY HUGE SAFETY ISSUE.

NHTSA ID

10991966

Incident

May 17, 2017

THE ALL ACTIVITY MODULE (AAM) DOES NOT FUNCTION PROPERLY TO WHICH NEITHER SIDE MIRRORS CAN BE ADJUSTED BECAUSE THE WINDOWS NO GO UP AND DOWN OR LONGER OPERATE. THEN THE DOOR LOCKS NO LONGER FUNCTIONS AND VARIOUS OTHER COMPONENTS RELY SOLELY OFF OF THIS MIDDLE INSTRUMENT CLUSTER. WHEN I TOOK IT TO THE DEALER THEY SAID THERE IS A MALFUNCTION IN THE AAM CONTROLS WHICH ARE THE CAUSING AFFECT OF THIS ISSUE.

NHTSA ID

10934046

Incident

Dec 6, 2016

Mileage

150,000 mi

TL* THE CONTACT OWNS A 2001 MERCEDES BENZ ML430. THE CONTACT STATED THAT THE FOBIK UTILIZED AND THE LOCKS BEGAN TO LOCK AND UNLOCK SEVERAL TIMES UNTIL IT EVENTUALLY STOPPED AND UNLOCKED. THE CONTACT ALSO STATED THAT THE DOOR LOCK ON THE DRIVERS SIDE DOOR, LOCKED AND UNLOCK SEVERAL TIMES WHEN THE FOBIK WAS UTILIZED TO LOCK THE DOOR. THE CONTACT STATED THAT THE VEHICLE HAD TO BE LOCKED MANUALLY. THE FAILURE RECURRED EACH TIME THE FOBIK OR DOOR LOCK WAS DEPRESSED. THE VEHICLE WAS TAKEN TO THE DEALER AND WAS DIAGNOSED THAT THE ALL ACTIVITY MODULE NEEDED TO BE REPLACED. THE VEHICLE WAS NOT REPAIRED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE AND STATED THAT THE VIN WAS NOT INCLUDED IN NHTSA CAMPAIGN NUMBER: 01V061000 (ELECTRICAL SYSTEM). THE APPROXIMATE FAILURE MILEAGE WAS 109,000.

NHTSA ID

10778174

Incident

May 1, 2013

Mileage

109,000 mi

TL* THE CONTACT OWNS A 2001 MERCEDES BENZ ML430. THE CONTACT STATED THAT THE SERVICE ENGINE AND THE BAS ESP WARNING LIGHTS FLICKERED. THE CONTACT MENTIONED THAT WHEN THE WARNING LIGHTS ILLUMINATED, THE BRAKES ENGAGED AND THERE WAS AN ABNORMAL NOISE. IN ADDITION, THE ELECTRIC POWER DOOR LOCK FUNCTION WAS MAKING AN ABNORMAL NOISE. THE CONTACT DISCOVERED THAT THE A/C LINE FRACTURED AND THE WINDSHIELD WIPERS PLASTIC PIECE FRACTURED. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE VEHICLE WAS INCLUDED IN NHTSA CAMPAIGN NUMBER: 11V208000 (VEHICLE SPEED CONTROL). THE MANUFACTURER WAS NOTIFIED OF THE FAILURE. THE APPROXIMATE FAILURE MILEAGE WAS 186,675. UPDATED 11/23/15*LJ THE CONSUMER FIXED THE VEHICLE AT HIS/HER EXPENSE. UPDATED 01/29/16.*JB

NHTSA ID

10762937

Incident

Feb 5, 2015

Mileage

186,675 mi

Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once when changing from forward to reverse (and vice versa). Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to micromovement in the connection between the wheel bearing inner race and the joint housing of the side shaft. Note: The collar nut must always be replaced after being loosened and must be tightened to the specified torque. Remedy Coat contact surface of side shaft with wheel bearing with Molykote paint. To do this, proceed as follows: 1. Remove outboard side shafts (extract outer joint gearing from wheel hub) 2. Clean contact surface A (see picture file in attachment "Outer joint housing before") before coating with Molykote, using "spirit" (free of dust and grease) 3. Coat contact surface A (see image file in attachment "Outer joint housing after") using Molykote and leave to dry for one hour in removed condition 4. Reinstall side shafts Note: Before using the antifriction coating (Molykote), stir or shake it well (for at least 1 minute).

Complaint Single throttle lift-off clunking noise from the side shaft when moving off (audible at the outboard end). The clunk is heard once when changing from forward to reverse (and vice versa). Note: Sound file in attachment Cause If the complaint is eliminated by experimentally loosening the outboard collar nut (by 1 turn), the problem is due to micromovement in the connection between the wheel bearing inner race and the joint housing of the side shaft. Note: The collar nut must always be replaced after being loosened and must be tightened to the specified torque. Remedy Coat contact surface of side shaft with wheel bearing with Molykote paint. To do this, proceed as follows: 1. Remove outboard side shafts (extract outer joint gearing from wheel hub) 2. Clean contact surface A (see image file in attachment "Outer joint housing before") before coating with Molykote, using "spirit" (free of dust and grease) 3. Coat contact surface A (see image file in attachment "Outer joint housing after") using Molykote and leave to dry for one hour in removed condition 4. Reinstall side shafts

Complaint Headlamps leaking or fogged Cause The fogging of the headlamp is a natural phenomenon which can occur under certain climatic conditions. In contrast to a leaky headlamp, physical fogging does not result in a technical impairment of the headlamp. A leak test must be performed to determine if physical fogging exists or if the headlamp is leaky. Remedy Check for external damage: You can identify a damaged headlamp in the following way: For headlamps with a closed system 1. Check the headlamps for any external damage and check also for correct seating of the Gore-diaphragm/correct latching of the cover caps. 2. If the headlamp exhibits any external damage, replace the headlamp. For headlamps with an open system 1. Check the headlamps for any external damage and seal off the vent, then make sure the cover caps are latched correctly into place. 2. If the headlamp exhibits any external damage, replace the headlamp. Note: External damage to the headlamp does not present a warranty or goodwill case. 1. Clear fogged/condensed LED headlamps and LED rear lamps: 1. Drive the vehicle into the workshop (temperature higher than +18 °C/+64.4°F). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood or trunk. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable (thawing progress). 7. If the condensation has disappeared, nothing else has to be done. Note: If defrosting has been performed, you can skip the first step. 2. Leak test of headlamp with overpressure: • Connect test adapter to pressure tester. (Figure 1) • Check test adapter for leak tightness. To do so, connect plug and coupling (picture 2) and apply a maximum overpressure of 30 mbar. The pressure must remain constant. If the pressure does not remain constant, use a new adapter. • All vents have to be sealed with sealing compound and the existing diaphragm with the stamp (picture 3 [3]). (Picture 4) Make allowance for the different headlamp variants here (there are different outlet openings). • Check if the headlamp needs to be removed to gain access to the diagnostic socket on the headlamp housing. • Plug the adapter onto the diagnostic socket on the headlamp housing. (Picture 5). • Apply a maximum of 30 mbar overpressure to the headlamp housing. Note: If the maximum overpressure of 50 mbar is exceeded the headlamp seal will be damaged (picture 6). • If a pressure drop of less than 10 mbar is measured within 30 seconds, the headlamp is tight and there is natural physical condensation. • If a higher pressure drop than 10 mbar is measured within 30 seconds, the headlamp is leaky. Note: The leaky position can be localized with the aid of soap suds. If the pressure test is not passed, the headlamp is leaky. If the cause cannot be rectified, the headlamp must be replaced. Note: If the headlamp is replaced, no dry packs may be installed on the new replacement headlamp. AR82.10-P-5455WT was created for the pressure test. This AR can be used as a reference manual for all closed headlamps. In the event of an open headlamp system, the vent ducts must be sealed before the pressure test.

Complaint Headlamp, front fog lamp leaky or fogged Cause Fogging of the headlamps is a natural phenomenon, which can occur under certain climatic conditions. It does not lead to any technical impairment of the headlamp. Remedy NOTE: If a pressure compensation diaphragm is fitted in the housing cover, then the lamp unit is a "closed system". Headlamp: Remedy 1 Clearing fogged/condensed LED headlamps and LED rear lamps: 1. Drive vehicle into workshop (temperature higher than +18 °C/+64.4 °F) and connect the exhaust extraction. Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine and connect battery support via a charger. 3. Open the hood or trunk. 4. Switch on the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable (thawing progress). Clearing fogged/condensed halogen/xenon headlamps: 1. Drive the vehicle into the workshop (temperature higher than +18 °C/+64.4°F). Note: Do not perform an engine wash before the defogging test. 2. Switch off the engine. 3. Open the hood. 4. Switch off the lights. 5. Leave the vehicle in this state for 60 minutes. 6. Check for formation of condensation, a significant reduction in the formation of condensation must be clearly recognizable (thawing progress). Note: If there is no visible reduction in the formation of condensation, check the headlamp for damage. (See Remedy 2) It is not physically possible to defog the headlamps completely. Fogging does not impair the operation or the service life of the headlamp. Remedy 2 A damaged headlamp can be identified as follows: 1. Check the headlamp for external damage and that the cover caps and the diaphragm are correctly seated. 2. Check the electrical connectors of the plugs and pins. 3. Check for leak tightness in accordance with LI82.10-P-078896 The test can only be conducted on headlamps. 4. If the headlamp or the rear lamp has any external damage, replace the component part in accordance with the WIS instructions.

Complaint Vehicle with atypical reduced heat output. Cause Silicate granulate may have escaped from a damaged bag in the expansion reservoir (not visible), reducing the coolant flow in the heater heat exchanger (see picture). Remedy With the aforementioned complaint, make sure that the cooling circuit is inspected for silicate residues after all standard tests are completed. The silicate residues tend to accumulate upstream of the shutoff valve for the heater hot water pulsed valve. If there are silicate residues in the coolant, the engine must be flushed thoroughly. To make sure that all silicate residues are removed from the cooling circuit, the following parts must also be replaced (cleaning of these components is not sufficient): Coolant expansion reservoir, radiator, oil/water heat exchanger (oil cooler), heater valve, heat exchanger of heater, coolant and, if installed, the electric water pump for the residual heat utilization system. Determine the parts for the respective vehicle in the EPC.

Complaint During a phone call, the called party has difficulty understanding/cannot understand the driver, or interference/background noises are audible to the called party during a call. It becomes increasingly difficult to understand as the speed rises. Cause A. Seating of the microphones in the headliner. Side edges are covered by the textile cover (see picture "1") B. Assembly of microphones (B25/20 or B25/21) in the headliner. C. Dirt inside the microphone housing Remedy 1. Press finger on rear of microphone (on adhesive tape) 2. Remove microphone cap from the front 3. Eliminate protruding material residues of the microphone cutout at the headliner, e.g. with a soldering iron. The microphone must be seated in the headliner as shown in picture "2". 4. Push microphone from behind until it is firmly pressed into the headliner 5. Maintain pressure and press/clip cap into microphone from the front. Note: The cover cap must be clearly heard and felt to engage. 6. This procedure must be carried out on both microphones (B25/20 and B25/21) Note: • It is recommended to replace the cover caps. • The non-woven cloth in the cover cap protects the microphone from soiling and must not be removed. NOTE: The information contained in this document is intended for use by trained, professional technicians with the knowledge to properly and safely perform diagnosis and repairs on Mercedes-Benz vehicles, using Mercedes-Benz approved tools and equipment. It informs service technicians about conditions that could occur in certain vehicles and provides information that could assist in proper vehicle diagnosis, service, or repair. It does not indicate that a defect is present in any vehicle referenced in this document nor does it imply warranty coverage. DO NOT assume that a symptom or condition, or a described cause of a symptom or condition, affects any particular vehicle or groups of vehicles, or that a described repair applies to any particular vehicle or groups of vehicles. There can be multiple causes resulting in the same or similar symptoms or conditions described in this document, and trained professional service technicians must use their diagnostic skills to make evaluations on a case-by-case basis. The information contained in this document does not guarantee warranty coverage nor does it extend the vehicle’s warranty in any way.