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Mercedes-Benz engine repair questions and answers

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  • AutoMD Member
    AutoMD Member - 2000 Mercedes Benz ML430 - Engine - 11/2/2013
    The battery drained after park for 7 day nothing visual which cause it
    test and recharge battery than reinstall it will hold for few day
     
    0 answer
  • Cardis
    Cardis - 2007 Mercedes Benz R350 - Engine - 11/1/2013
    Vehicle began to hesitate and loose power on interstate in cruise mode. Has since lost power in city traffic.
    Newly purchased vehicle. When vehicle first exhibited problem it was taken to a local shop where it was tested for electrical codes and none were found. Engine light came on and onboard monitor states that: [It has been xxx days since "D" system has been ...
     
    0 answer
  • Cardis
    Cardis - 2007 Mercedes Benz R350 - Engine - 11/1/2013
    Vehicle began to hesitate and loose power on interstate in cruise mode. Has since lost power in city traffic.
    Newly purchased vehicle. When vehicle first exhibited problem it was taken to a local shop where it was tested for electrical codes and none were found. Engine light came on and onboard monitor states that: [It has been xxx days since "D" system has been ...
     
    0 answer
  • monty
    monty - 1996 Mercedes Benz E320 - Engine - 11/1/2013
    It surges at idle and taking off from stop but run ok on freeway
    I've change the massive air flow sensor already
     
    0 answer
  • AutoMD Member
    AutoMD Member - 2008 Mercedes Benz E350 - Engine - 10/19/2013
    Car does not start after parked in driveway last night?
    Lights and display works. Turning key does nothing to start however clock runs backwards and stops on current time after doing 24 hr resolution.
     
    0 answer
  • AutoMD Member
    AutoMD Member - 2007 Mercedes Benz ML500 - Engine - 10/19/2013
    Metal grinding sound
    I just had the compressor replaced, now I hear a grinding sound when driving slow and turning the steering wheel
     
    0 answer
  • gutierrezrichard32
    gutierrezrichard32 - 2000 Mercedes Benz ML320 - Engine - 10/6/2013
    Why does the starter have a clicking noise and does not rotate when key is turned to start position
    replaced starter and it still remains the same
     
    • HouseCallAuto
      10/6/2013 HouseCallAuto
      Are there any error messages showing on the information center? Like "start error" for example?
  • Michael Olsen
    Michael Olsen - 2000 Mercedes Benz ML320 - Engine - 9/27/2013
    Water seems to empty from reservoir
    water level light comes on water is gone from sysem after driving
     
    • John's Auto Repair
      9/27/2013 John's Auto Repair
      Could be a slow leak in the cooling system. Have the cooling system pressure tested
      to find the leak.
  • abcrtz
    abcrtz - 1988 Mercedes Benz 560SEL - Engine - 9/27/2013
    Why does my car die on me
    My 560 starts and idles fine in the drive way. As soon as I step on the accelerator it dies on me.
     
    0 answer
  • joanne.bermudez
    joanne.bermudez - 2007 Mercedes Benz C230 - Engine - 9/25/2013
    Check engine light on
    intake manifold gasket was just changed a week ago
     
    • Jimm
      9/25/2013 Jimm
      The check engine light is located on the dash and stays on if the computerized engine control system detects an engine performance or emissions problem.
      First step - have the stored fault codes or check engine light scanned - for free - at any local auto parts store; Advance Auto, Auto Zone, NAPA. Then, post a reply as 'add answer' with the specific code for more assistance. There may be a fault code stored in the OBD memory which may not be displayed as a check engine light
  • rmcelroy1
    rmcelroy1 - 2003 Mercedes Benz ML320 - Engine - 9/20/2013
    My car will not start right away. Turns over many times before it fires
    It happens more after sitting .
     
    0 answer
  • UCME48
    UCME48 - 2001 Mercedes Benz SLK320 - Engine - 9/14/2013
    Need to pin point the # 4 plug #5 pin in the ECM to correct a short
    Im having ny ecm rebuilt and he found that on the ecm the #4 plug #5 pin was the problem, I need help in pin pointing the wire and its use,,thanks, Don
     
    • HouseCallAuto
      9/13/2013 HouseCallAuto
      The #4 cylinder and #5 pin is a wire that runs from pin 5 of the engine control module to pin 3 of the ignition coil for the #4 cylinder. If this is what was failed within the ecm then replace the ignition coil for cylinder #4 and confirm that this blue white wire is not shorted to ground anywhere alomng the run form the ecm to the coil and if it is too difficult to follow the full length of the wire to see it then run a new wire and splice it a few inches away from the ecm and a few inches away from the coil. Done.
      HouseCallAuto
      9/13/2013 UCME48
      I didnt explainmyself very well, im speaking of the ECM #4 SOCKET and the #5 pin in the socket, ita a brown wire i think goes to the 02 sensors. Sorry about the confusion
    • HouseCallAuto
      9/14/2013 HouseCallAuto
      Ok I see a brown wire that runs from the #5 ecu pin and goes to both DOWNSTREAM O2 sensors. Probable cause of ecu failure is a shorted out O2 sensor heater. That means replace both rear O2 sensors and confirm that this brown wire is not shorted to any other wires. O2 sensor is the more likely cause.
      HouseCallAuto
      9/14/2013 UCME48
      Thanks so much for your help, I will change both and check before i get finished,, Thanks again,,,,,Don
  • UCME48
    UCME48 - 2001 Mercedes Benz SLK320 - Engine - 9/11/2013
    ECM plug 4 #5 pin what does it control
    Im having my ecm rebuilt and they found that the #4 plug #5 pin was the cause of my short, My Alldata diagram showes a different wire sequence then mine does..
     
    0 answer
  • jpuett
    jpuett - 1998 Mercedes Benz ML320 - Engine - 9/10/2013
    How to install combination switch assembly on vehicle
    do you have to remove steering wheel
     
    • bear.1216
      9/10/2013 bear.1216
      You have to remove steering wheel and disassemble steering column until you reach the switch.
  • UCME48
    UCME48 - 2001 Mercedes Benz SLK320 - Engine - 9/7/2013
    O2s sensor shorted ecm
    I sent my ECM in to be rebuilt and after looking it over he found that the O2s sensor on the left bank low side after the TWC was the cause of my short. any ideas on why this sensor could effect and distroy my ECM, I did find that it had some oil on it >>
     
    • Jimm
      9/7/2013 Jimm
      The ECM monitors / looks for a signal from the O2 sensors of a certain milliamp (mA) and voltage range (variation) during the O2 sensor normal operation. The O2 sensor produces a voltage based on oxygen content in the exhaust. The voltage varies between 0.1 and 0.9 Volts, with 0.1 indicating lean and 0.9 indicating rich. The ECM constantly monitors this voltage while in closed loop to determine how much fuel to inject. If the ECM determines that the O2 sensor voltage was too low (less than 0.4 Volts) for too long (for more than 20 seconds (time varies with model)), then a fault code is set in the OBD (On-board diagnostic) system.
      If there is a short in the O2 sensor or the sensor wiring, then the ECM will simply have an out-of-range signal and will not be able to monitor. It is unlikely the O2 sensor has directly caused the ECM malfunction or failure.

      Today’s sensors are quite sophisticated and rarely require replacement unless they are brought outside of their operating window due to engine malfunction or contamination. On OBD II equipped vehicles, the ECM monitors 02 sensor voltages and triggers a check engine light if the voltages fall outside a predetermined value. A bad sensor is reasonably easy to diagnose with a common scan tool. The voltage of the front sensor should fluctuate rapidly from approximately 200-800 millivolts, if it does not or does it slowly, chances are the sensor is bad. However, it is very difficult to detect a functional but degraded oxygen sensor. They do however, even during perfect operating conditions, degrade over time due to the depletion of the platinum electrodes inside the sensor.
      As they degrade, the output voltage is reduced and as the output voltage is reduced, the ECM compensates from what it reads as a lean A/F ratio, compensating by adding more fuel. An increase in fuel consumption not remedied by a tune up often points to an oxygen sensor that has deteriorated.