2001 Mercedes-Benz ML55

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.

While driving the vehicle the car would randomly lock up different wheels on the car jerking the steering wheel out of my hands. The first time I was on a freeway and thought I must have run over a puddle of oil and the antilock system was trying to keep the car stable, even though the steering wheel was jerking from side to side. As it only last 10 terrifying seconds, I thought that would be the last time the car did that. The second time it happened was just getting off the freeway and the system kept locking up different wheels again, but this time it would not stop. I had to limp the car to an area where I could safely park it out of traffic and call a tow truck to take us home. Doing research on this it seems this is a common problem with this model of Mercedes as well as a few more models. It comes up in a simple Google search. I am grateful I was the person driving the car at the time and not my wife. This is her daily driving car and I really want to be able to trust the car for her to drive it again.

NHTSA ID

11568459

Incident

Jan 27, 2024

TL* THE CONTACT OWNS A 2001 MERCEDES-BENZ ML55AMG. WHILE DRIVING 45 MPH, THE FRONT PASSENGER SIDE BRAKE INDEPENDENTLY LOCKED WITHOUT WARNING AND THE VEHICLE WENT SIDEWAYS. THE DEALER AND MANUFACTURER WERE NOT NOTIFIED. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE FAILURE MILEAGE WAS 135,000.

NHTSA ID

11004151

Incident

Jul 9, 2017

Mileage

135,000 mi

TL* THE CONTACT OWNS A 2001 MERCEDES-BENZ ML55. WHILE DRIVING VARIOUS SPEEDS, THE VEHICLE BECAME VERY HARD TO STEER. THE VEHICLE WAS TAKEN TO THE DEALER WHERE IT DIAGNOSED THAT THE POWER STEERING HOSE HAD NUMEROUS LEAKS AND WOULD NEED TO BE REPLACED. THE VEHICLE WAS REPAIRED. THE VEHICLE WAS PREVIOUSLY SERVICED UNDER NHTSA CAMPAIGN NUMBER: 03V121000 (STEERING), BUT THE REMEDY FAILED TO REPAIR THE VEHICLE. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS 116,000.

NHTSA ID

10854402

Incident

Mar 31, 2016

Mileage

116,000 mi

2001 MERCEDES BENZ ML55. CONSUMER WRITES IN REGARDS TO A DEFECTIVE SENSOR MALFUNCTION. *SMD THE CONSUMER STATED THE LEFT FRONT TIRE LOCKED UP, SENDING THE VEHICLE INTO THE OPPOSITE LANE OF TRAFFIC. THE CONSUMER LOST CONTROL OF THE VEHICLE AND ROLLED OVER. THE CONSUMER STATED THE SENSOR DID NOT PREVENT THE ROLL OVER. *JB

NHTSA ID

10679161

Incident

Nov 20, 2013

2001 MERCEDES-BENZ ML55, DEFECTIVE SENSOR NEAR THE RIGHT FRONT TIRE THAT WHEN FUNCTIONING IS SUPPOSE TO PREVENT ROLL OVERS. UPDATED 02/12/15*BF THE CONSUMER STATED THE RIGHT FRONT TIRE LOCKED UP AND HE GRABBED THE WHEEL TO PREVENT TO AVOID HITTING PARKED VEHICLES. HE STEERED LEFT, MAKING A U-TURN FACING ONCOMING TRAFFIC, AVOIDING A COLLISION AND UPON OVER-COMPENSATING FOR THE MALFUNCTION OF THE VEHICLE, HE FLIPPED OVER TWICE AND THE WAS STOPPED BY A HITTING A LIGHT POLE. *JB

NHTSA ID

10683338

Incident

Nov 20, 2013

TL* THE CONTACT OWNS A 2001 MERCEDES ML55. THE CONTACT STATED THAT THE VEHICLE WAS EXHIBITING BRAKING ISSUES AND WAS TAKEN TO THE DEALER. THE DEALER FOUND THAT THE LATERAL ACCELERATION SENSOR NEEDED TO BE REPLACED. THE VEHICLE WAS REPAIRED BUT THE FAILURE RECURRED WITHIN THREE WEEKS OF THE REPAIR. THE CONTACT WAS DRIVING THROUGH A CAR WASH WHEN THE VEHICLE ABNORMALLY ACCELERATED, THE CONSUMER'S FOOT WAS ON THE BRAKE, BUT THE VEHICLE WENT OVER SOME HUGE BOULDER ROCKS AND WENT AIRBORNE AND LANDED HARD ON GROUND, TIRES FIRST. . THE CONTACT WAS REPORTED AS INJURED. A POLICE REPORT WAS NOT FILED OF THE INCIDENT. THE VEHICLE WAS NOT REPAIRED. THE CURRENT AND THE FAILURE MILEAGE WAS 79,836. THE CONSUMER STATED THE ESP AND BAS LIGHTS ILLUMINATED AFTER THE INCIDENT. UPDATED 03/16/12

NHTSA ID

10439053

Incident

Jul 3, 2011

Mileage

79,836 mi

TL*THE CONTACT OWNS A 2001 MERCEDES BENZ ML55. WHILE DRIVING 25 MPH THE BRAKES WERE APPLIED AND THEN RELEASED CAUSING THE WHEELS TO LOCK. THE VEHICLE BECAME UNCONTROLLABLE AND HAD TO BE PARKED. THE VEHICLE WAS TAKEN TO THE DEALER WHO STATED THAT THE SENSOR FAILED AND CAUSED THE COMPUTER AND WHEELS TO LOCK. THERE ARE NO RECALLS OR WARRANTIES RELATED TO THE FAILURE. HE IS RESPONSIBLE FOR PAYING $3400 TO REPAIR THE VEHICLE AND A DIAGNOSTIC TEST. THE MANUFACTURER WAS CONTACTED AND STATED THAT HE HAD TO CHECK WITH THE DEALER IN HIS AREA AND OFFERED NO OTHER ASSISTANCE. THE VIN WAS UNAVAILABLE. THE FAILURE MILEAGE WAS 25,000.

NHTSA ID

10370718

Incident

Apr 15, 2009

Mileage

25,000 mi

HEADLIGHTS INTERMITTENTLY GOING OFF WHILE DRIVING, FOG LIGHTS QUIT WORKING, CAN GET NO LIGHTS TO COME ON SOMETIMES WHILE DRIVING. HAVE RESEARCHED AND FOUND THAT THERE HAS ALREADY BEEN A RECALL PUT OUT ON MY VEHICLE ACCORDING TO CARFAX, YET WHEN I SPEAK TO ANYONE AT MERCEDES-BENZ, THEY SAY MY CAR IS NOT INCLUDED AND WILL NOT DO ANYTHING TO HELP. *TR

NHTSA ID

10296899

Incident

Dec 8, 2009

Mileage

99,781 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.