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Pete, Mercedes Mechanic
Category: Mercedes
Satisfied Customers: 27825
Experience:  Over 15 years experience as a Mercedes dealer technician
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Pearl, i have a 2008 ML 320 bluetech. no check engine light

Customer Question

Hi Pearl, i have a 2008 ML 320 bluetech. no check engine light is on, cleared codes after replacing up stream temp sensor at the catalytic convertor. I have 7 monitors set, but the cat monitor will not set. drove for six minutes on the freeway at 65 MPH without braking, the at 35MPH for 6 stops. Did that twice still wont set. any ideas? thanks, Bruce.
JA: The mechanics have tons of experience in that area. Do you happen to have the code?
Customer: No Unfortunately.
JA: Not a problem. You can work with the Mercedes Mechanic to figure that out.
Customer: I am a Mercedes Mechanic
JA: Are you hoping to fix this yourself?
Customer: Yes, I need the drive cycle
to get the Cat monitor set.
JA: Great! What have you tried so far?
Customer: 65 Mph on freeway for 6 minutes without braking, then 6 stops after driving at 35MPH on the side streets.
JA: Is there anything else important you think the Mercedes Mechanic should know about your Mercedes?
Customer: No
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Mercedes Mechanic about your situation and then connect you two.
Submitted: 1 year ago.
Category: Mercedes
Expert:  Pete replied 1 year ago.
Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay. This can be a difficult monitor to run and set and can take hot start/cold starts etc.Below is the procedure I follow to help speed up the process of running all monitors/testing. Cold Start The barometric pressure (BARO) is more than 81 kPa. The engine coolant temperature (ECT) is between (41-86°F). The intake air temperature (IAT) is between (41-86°F). The start-up ECT and IAT are within (16°F) of each other. The battery voltage is between 9-16 volts. The fuel level is between 15-85 percent. Important: Whenever the ignition is turned ON, ignition positive voltage is supplied to the HO2S heaters. After verifying the enable criteria, turn OFF the ignition for approximately 5 minutes to allow the sensors to cool before continuing with the test. Once the engine is started, DO NOT turn the engine OFF for the remaining portion of the set procedure.Turn OFF all of the accessories, Set the vehicle parking brake. Verify the transmission is in Park for automatic transmissions and Neutral for manual transmissions. Start the engine and allow the engine to idle for 2 minutes.Acceleration at part throttle to (55 mph) with this speed maintained until the engine reaches operating temperature. This may be up to 8 minutes depending on the start up coolant temperature. Continued operation under these conditions for an additional 6 minutes. Acceleration at part throttle to (45-55 mph) with this speed maintained for 2 minutes. Deceleration to (0 mph). Engine idling for 2 minutes while the following criteria is maintained: The service brake is depressed. The automatic transmission is in drive. The manual transmission is in neutral with the clutch pedal depressed If more help is needed, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service.You can rate at any time and we can continue to work on your question as this will not close out your question.Keep in mind in some cases it can be difficult to fully diagnose or help repair your vehicle without seeing it and I work on delivering the best possible answer from what I see to work with.Thanks Pete
Customer: replied 1 year ago.
The explanation wont print, only my chat with Pearl prints. ??????????????????
Expert:  Pete replied 1 year ago.
Try highlighting what I posted above holding down the left click on your mouse and highlight over all the wording.Once this is done right click the highlighted area and select print when the box pops up. Let me know if you need anything else and feel free to rate my help here. Thanks Pete
Customer: replied 1 year ago.
its is still hyrogliphics
Expert:  Pete replied 1 year ago.
That is odd.Try this link here instead. Thanks Pete
Customer: replied 1 year ago.
Thanks, ***** *****
Expert:  Pete replied 1 year ago.
Your welcome Let me know if you need anything else and feel free to rate my help here. Thanks Pete