NHTSA owner reports · September 18, 2026 snapshot.
Service Brakes complaints
15 reportsClear category filter198,000 miles · May 3, 2024
Service BrakesWheels
The contact owns a 2002 Mercedes-Benz ML320. The contact stated while driving at approximately 25 MPH, the driver’s side front wheel independently braked. The contact stated he had not depressed the brake pedal but heard an abnormal sound from the tire screeching as the wheel had stopped rolling. The contact stated that the ESP …
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The contact owns a 2002 Mercedes-Benz ML320. The contact stated while driving at approximately 25 MPH, the driver’s side front wheel independently braked. The contact stated he had not depressed the brake pedal but heard an abnormal sound from the tire screeching as the wheel had stopped rolling. The contact stated that the ESP traction warning light was illuminated. The contact pulled the vehicle over, turned off, restarted the vehicle, and was able to continue driving. The contact stated that the failure occurred several minutes later. The contact stated that the failure occurred one other time and had not happened again. The contact had not taken the vehicle to a local dealer or independent. The vehicle had not been diagnosed and was not repaired. The manufacturer was not informed of the failure. The failure mileage was approximately 198,000.
NHTSA ODI #11586737
Mileage unknown · Apr 30, 2022
Forward Collision AvoidanceService Brakes
The car brakes suddenly by itself just after the ESB/ABS lights come on along with an exclamation point (!). This has happened randomly at least 4 times since we purchased the car. Once at high speeds on the highway. It appears this problem is common with other owners of Mercedes 2001-2002 ML's. According to the forums below, th…
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The car brakes suddenly by itself just after the ESB/ABS lights come on along with an exclamation point (!). This has happened randomly at least 4 times since we purchased the car. Once at high speeds on the highway. It appears this problem is common with other owners of Mercedes 2001-2002 ML's. According to the forums below, the problem seems to be a "YAW RATE SENSOR" malfunction or defect. My Mercedes mechanic saw no error codes for this component and it seem extremely expensive (forum states part is $3000) to replace. The https://mbworld.org/forums/m-class-w163/233486-big-problems-ml320-pls-help-2.html
NHTSA ODI #11462862
203,000 miles · Jan 11, 2020
Electrical SystemService BrakesWheels
FUSE BOX SOME HAS POWER SOME NOT. FRONT LEFT WHEEL MAKING THIS NOISE AND STOPS AFTER 25 MILES PER HOUR RADIO VOLUME LOW WHEN IGNITION KEY IS ON POSITION 3 WHEN KEY IT'S IN THE POSITION 2 LAUD VOLUME WHEN KEY IS NOT IN I CAN TURN ON THE STEREO
NHTSA ODI #11298583
106,500 miles · Dec 31, 2017
Electrical SystemElectronic Stability Control (esc)Service Brakes
I WAS DRIVING ON A BUSY INTERSECTION IN MY 2002 MERCEDES BENZ ML320 WHEN DRIVING THE YELLOW TRIANGLE IN THE SPEEDOMETER STARTS TO FLASH AND ALL THE BREAKS LOCK UP, THIS IS FOLLOWED BY A STALL, THANKFULLY I WAS ABLE TO PULL OFF TO THE SIDE OF THE ROAD WITHOUT BEING HIT. AFTER DOING SOME RESEARCH I DISCOVERED THAT MANY MERCEDES ML…
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I WAS DRIVING ON A BUSY INTERSECTION IN MY 2002 MERCEDES BENZ ML320 WHEN DRIVING THE YELLOW TRIANGLE IN THE SPEEDOMETER STARTS TO FLASH AND ALL THE BREAKS LOCK UP, THIS IS FOLLOWED BY A STALL, THANKFULLY I WAS ABLE TO PULL OFF TO THE SIDE OF THE ROAD WITHOUT BEING HIT. AFTER DOING SOME RESEARCH I DISCOVERED THAT MANY MERCEDES ML320 OWNERS WERE HAVING THIS SAME PROBLEM. SPECIFICALLY THE YAW RATE SENSOR. THIS IS A SERIOUS LIFE THREATENING ISSUE THAT CAN INJURE OR WORSE YET KILL SOMEONE. YOU GUYS NEED TO DO A RECALL BEFORE SOMEONE DIES!
NHTSA ODI #11057753
135,000 miles · Nov 3, 2016
Electronic Stability Control (esc)Service Brakes
ON NUMEROUS OCCASIONS OCCURRING IN DIFFERENT CONDITIONS REGARDING SPEED, WEATHER, ROAD CONDITIONS, ETC., I HAVE HAD THE VEHICLE PULL HARD TO THE RIGHT WHILE ENGAGING THE FRONT BRAKES, BOTH WHILE TURNING THE VEHICLE AND ON STRAIGHTAWAYS. WHEN THIS OCCURS, THE TRIANGLE HAZARD LIGHT AND ESP LIGHTS START FLASHING. MOST OFTEN I HA…
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ON NUMEROUS OCCASIONS OCCURRING IN DIFFERENT CONDITIONS REGARDING SPEED, WEATHER, ROAD CONDITIONS, ETC., I HAVE HAD THE VEHICLE PULL HARD TO THE RIGHT WHILE ENGAGING THE FRONT BRAKES, BOTH WHILE TURNING THE VEHICLE AND ON STRAIGHTAWAYS. WHEN THIS OCCURS, THE TRIANGLE HAZARD LIGHT AND ESP LIGHTS START FLASHING. MOST OFTEN I HAVE BEEN ABLE TO PULL OFF TO THE SIDE OF THE ROAD, THANKFULLY SAFELY, OR ON ONE OCCASION STOP IN THE MIDDLE OF THE ROAD AS THE CAR WOULDN'T ALLOW ME TO CONTINUE DRIVING WHICH WAS INCREDIBLY DANGEROUS AND SCARY. I HAVE TAKEN IT TO THE DEALERSHIP WHO REPLACED THE FRONT BRAKE SENSORS, WHICH DIDN'T FIX THE PROBLEM, AND RETURNED TO HAVE THEM AGAIN DIAGNOSE THE ISSUE AND DECLINED THEIR RECOMMENDATIONS SUCH AS REPLACING THE BACK BRAKE SENSORS, UNTIL I CAME UPON THE REPEATED ISSUES OF THE STABILITY SENSORS FAILING (SPECIFICALLY THE YAW SENSOR). I CAN'T BELIEVE THAT, TO DATE, THIS HAS NOT BEEN A RECALL ISSUE AND NO ONE HAS BEEN SERIOUSLY INJURED OR KILLED DUE TO THIS PROBLEM (I FILED A PREVIOUS CLAIM, BUT THE WEBSITE WENT UNDER MAINTENANCE AND CLOSED MY COMPLAINT AS I WAS FILING AND WAS GIVEN ID #10923983, BUT THERE IS NO INFORMATION FILED IN ASSOCIATION THAT I COULD FIND HENCE THE RE-FILING). *TR
NHTSA ODI #10923995
135,000 miles · Nov 3, 2016
Electronic Stability Control (esc)Service Brakes
ON MULTIPLE OCCASIONS AND NUMEROUS DIFFERENT SPEEDS, WEATHER, BOTH DRIVING ON A STRAIGHTAWAY OR TURNING, AND OTHER ROAD CONDITIONS, THE FRONT BRAKES HAVE LOCKED UP ON THE CAR CAUSING IT TO VEER RIGHT WHILE ENGAGING THE BRAKES. MOST OFTEN I HAVE HAD TO PULL OVER, THANKFULLY SAFELY, OR ON ONE OCCASION, STOP IN THE MIDDLE OF THE R…
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ON MULTIPLE OCCASIONS AND NUMEROUS DIFFERENT SPEEDS, WEATHER, BOTH DRIVING ON A STRAIGHTAWAY OR TURNING, AND OTHER ROAD CONDITIONS, THE FRONT BRAKES HAVE LOCKED UP ON THE CAR CAUSING IT TO VEER RIGHT WHILE ENGAGING THE BRAKES. MOST OFTEN I HAVE HAD TO PULL OVER, THANKFULLY SAFELY, OR ON ONE OCCASION, STOP IN THE MIDDLE OF THE ROAD TO TURN THE CAR OFF TO BE ABLE TO CONTINUE DRIVING WHICH IS INCREDIBLY DANGEROUS AND SCARY. I'VE TAKEN IT TO THE DEALERSHIP AND THEY HAD ME REPLACE THE BRAKE SENSORS WHICH WERE OBVIOUSLY NOT THE PROBLEM AND THEN RECOMMENDED OTHER REPLACEMENTS, SINCE THE PROBLEM CONTINUED, THAT I DECLINED UNTIL I FOUND THAT THIS WAS A COMMON PROBLEM WITH THE STABILITY SENSORS IN THIS VEHICLE (SPECIFICALLY THE YAW SENSOR). I'M AMAZED THIS IS NOT A RECALL SITUATION AND THAT NO ONE HAS BEEN SERIOUSLY INJURED OR KILLED DUE TO THIS PROBLEM. *TR
NHTSA ODI #10923983
144,000 miles · Aug 9, 2016
Service BrakesVehicle Speed Control
TL* THE CONTACT OWNS A 2002 MERCEDES BENZ ML320. THE CONTACT STATED THAT WHILE DRIVING AT 60 MPH, THE BRAKES INDEPENDENTLY ENGAGED AND CAUSED THE VEHICLE TO VEER TO THE SIDE OF THE ROAD. THE CONTACT MENTIONED THAT THE ABS WARNING LIGHT ILLUMINATED AND THEN THE ENTIRE INSTRUMENT PANEL ILLUMINATED. THE VEHICLE WAS RESTARTED BUT TH…
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TL* THE CONTACT OWNS A 2002 MERCEDES BENZ ML320. THE CONTACT STATED THAT WHILE DRIVING AT 60 MPH, THE BRAKES INDEPENDENTLY ENGAGED AND CAUSED THE VEHICLE TO VEER TO THE SIDE OF THE ROAD. THE CONTACT MENTIONED THAT THE ABS WARNING LIGHT ILLUMINATED AND THEN THE ENTIRE INSTRUMENT PANEL ILLUMINATED. THE VEHICLE WAS RESTARTED BUT THE FAILURE RECURRED INTERMITTENTLY. THE VEHICLE WAS TAKEN TO AN INDEPENDENT MECHANIC WHERE IT WAS DIAGNOSED THAT THE BRAKE LAMP SWITCH FAILED. THE VEHICLE WAS NOT REPAIRED. THE CONTACT MENTIONED THAT THE VIN WAS INCLUDED IN NHTSA CAMPAIGN NUMBER: 11V208000 (VEHICLE SPEED CONTROL). THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURE. THE FAILURE MILEAGE WAS 144,000.
NHTSA ODI #10894297
600,014 miles · Jul 25, 2016
Service Brakes
BRAKES APPLIED ON THEIR OWN WITHOUT PEDAL PRESSURE WHILE CAR WAS MOVING AT HIGHWAY SPEED. FRONT BRAKES WERE SMOKING BY THE TIME I FOUND A SAFE PLACE TO STOP OFF THE 4-LANE ROAD ON A SIDE ROAD. REAR BRAKES SEEMED HOT, BUT NOT SMOKING. NO WARNING LIGHTS CAME ON. IMMEDIATELY BEFORE THIS HIGHWAY EVENT, CAR HAD JUST BEEN TRAVELING…
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BRAKES APPLIED ON THEIR OWN WITHOUT PEDAL PRESSURE WHILE CAR WAS MOVING AT HIGHWAY SPEED. FRONT BRAKES WERE SMOKING BY THE TIME I FOUND A SAFE PLACE TO STOP OFF THE 4-LANE ROAD ON A SIDE ROAD. REAR BRAKES SEEMED HOT, BUT NOT SMOKING. NO WARNING LIGHTS CAME ON. IMMEDIATELY BEFORE THIS HIGHWAY EVENT, CAR HAD JUST BEEN TRAVELING AROUND 35 MPH ON HILLY SIDE ROADS WITH STEEP ASCENTS AND DESCENTS. THIS IS THE FOURTH TIME BRAKES HAVE SELF-APPLIED IN A SIMILAR MANNER. AFTER SECOND EVENT, DEALER EXAMINED CAR BUT COULD NOT REPRODUCE THE PROBLEM OR FIND ANY FAULTS ON COMPUTER DIAGNOSTICS. WHEN BRAKES COOL, CAR RESTARTS WITHOUT BRAKES COMING ON. BRAKE PADS AND SENSORS WERE REPLACED 6,000 MILES EARLIER; SIGNIFICANT BRAKE DRAG WAS PRESENT FOR AROUND TWO HUNDRED MILES AFTER THAT REPAIR; DEALER SAID BRAKES WERE SELF-ADJUSTING AND DECLINED TO EXAMINE CAR AT THAT TIME. IT WAS ABOUT 4,000 MILES AFTER BRAKE PAD/SENSOR REPLACEMENT THAT THE SELF-BRAKING PROBLEM STARTED.
NHTSA ODI #10888170
175,000 miles · Mar 1, 2016
Electrical SystemService Brakes
TL* THE CONTACT OWNS A 2002 MERCEDES-BENZ ML320. WHILE DRIVING 10 MPH, THE VEHICLE FELT AS IF IT SLAMMED ON THE BRAKES WITHOUT THE CONTACT DEPRESSING THE BRAKE PEDAL. THE CONTACT STATED THAT THE EBS AND ABS WARNING LIGHTS REMAINED ILLUMINATED. THE CONTACT ALSO STATED THAT THE VEHICLE MADE A LOUD SCREECHING SOUND WHEN BEING DRIVE…
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TL* THE CONTACT OWNS A 2002 MERCEDES-BENZ ML320. WHILE DRIVING 10 MPH, THE VEHICLE FELT AS IF IT SLAMMED ON THE BRAKES WITHOUT THE CONTACT DEPRESSING THE BRAKE PEDAL. THE CONTACT STATED THAT THE EBS AND ABS WARNING LIGHTS REMAINED ILLUMINATED. THE CONTACT ALSO STATED THAT THE VEHICLE MADE A LOUD SCREECHING SOUND WHEN BEING DRIVEN. THE VEHICLE WAS TAKEN TO A LOCAL MECHANIC WHERE IT COULD NOT BE DIAGNOSED. THE MANUFACTURER WAS MADE AWARE OF THE FAILURE. THE FAILURE MILEAGE WAS APPROXIMATELY 175,000.
NHTSA ODI #10839233
139,000 miles · Jun 2, 2015
Electronic Stability Control (esc)Service Brakes
TL* THE CONTACT OWNS A 2002 MERCEDES BENZ ML320. WHILE DRIVING APPROXIMATELY 45 MPH, THE FRONT BRAKES ACTIVATED INDEPENDENTLY. THE CONTACT NOTICED THAT THE FRONT ROTORS WERE RED AND HOT. THE ESP WARNING LIGHT ILLUMINATED. THE CONTACT DISCONNECTED THE ESP CABLE AND CONTINUED TO DRIVE THE VEHICLE. THE MANUFACTURER WAS NOT NOTIFIED…
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TL* THE CONTACT OWNS A 2002 MERCEDES BENZ ML320. WHILE DRIVING APPROXIMATELY 45 MPH, THE FRONT BRAKES ACTIVATED INDEPENDENTLY. THE CONTACT NOTICED THAT THE FRONT ROTORS WERE RED AND HOT. THE ESP WARNING LIGHT ILLUMINATED. THE CONTACT DISCONNECTED THE ESP CABLE AND CONTINUED TO DRIVE THE VEHICLE. THE MANUFACTURER WAS NOT NOTIFIED OF THE FAILURES. THE VEHICLE WAS NOT DIAGNOSED OR REPAIRED. THE VIN WAS UNAVAILABLE. THE APPROXIMATE FAILURE MILEAGE WAS 139,000. UPDATED 7/21/15*CN UPDATED 10/18/2017*CN
NHTSA ODI #10723025
NHTSA investigations
1PE10050 · Brake Lamp Switch Failure.
Opened Dec 21, 2010 · Closed May 4, 2011
Status: closed (inferred from source dates) · Exterior Lighting:brake Lights:switch; Service Brakes, Hydraulic; Vehicle Speed Control; Vehicle Speed Control:cruise Control
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
Additional source detail variants (4)
Exterior Lighting:brake Lights:switch
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
Service Brakes, Hydraulic
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
Vehicle Speed Control:cruise Control
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
Vehicle Speed Control
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
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