2000 Mercedes Benz ML320 problems

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

PE10050

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 the federal safety agency 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.

PE07007

The office of defects investigation (odi) opened this preliminary evaluation to investigate allegations of engine crankshaft pulley harmonic balancer failure that could result in loss of power-steering assist.odi has received a total of 546 non-duplicative reports that allege engine crankshaft pulley harmonic balancer failure on all mercedes-benz vehicles using the subject component.the subject component failures are progressive in nature and only a small percentage of the complaints and warrant claims involved a failure that had progressed far enough to effect power steering performance (6 of 55 odi complaints reference increased steering effort).there have been no crashes or injuries related to the alleged defect.a safety-related defect has not been identified at this time and further use of agency resources does not appear to be warranted.accordingly, this investigation is closed.the closing of this investigation does not constitute a finding by the federal safety agency that a safety-related defect does not exist.the agency will take further action if warranted by the circumstances.see summary report attached for further detail.

PE03058

The hose clamp used to secure the power steering fluid cooling hose to the steering fluid cooler may not provide sufficient clamping force for the connection.the loss of power steering fluid may result in gradual reduction in power steering assist (I.e., increased steering effort) over time, with potential damage to the power steering pump. There have also been a few incidents of hose separation from the fitting, that have resulted in more rapid reductions of power steering.testing conducted by mercedes-benz indicates that the leaked fluid is not likely to be exposed to hot engine components.there are no known allegations that the defect condition has caused a vehicle fire. Mercedes-benz will conduct a voluntary recall campaign for the subject m-class vehicles.mercedes-benz will install a new hose clamp on the power steering hose to the power steering cooler of the subject vehicles.during clamp replacement, the power steering cooling hose will be inspected and replaced as necessary.

PE03006