Both downstream O2 sensor
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Both downstream O2 sensor
Hello,
I got 2012 E550 4matic and i would like to ask anyones help who can provide me the wiring diagram for bank 1 and 2 downstream O2 sensor, my vin WDDHF9BB2CA612581.. vehicle have check engine light for boost pressure leak but when i check parameters on idle both downstream o2 were not operational but no CEL related to O2. Did check the fuses front hood no issue found all were good… when weather permits will check the fuse box on the trunk. And while waiting for sunshine if i can get my hands on wiring diagram i can check from eCm connector if wiring is short thats causing the o2 to be not operational.
anyone’s help is highly appreciated.
thanks a lot!!!
regards,
I got 2012 E550 4matic and i would like to ask anyones help who can provide me the wiring diagram for bank 1 and 2 downstream O2 sensor, my vin WDDHF9BB2CA612581.. vehicle have check engine light for boost pressure leak but when i check parameters on idle both downstream o2 were not operational but no CEL related to O2. Did check the fuses front hood no issue found all were good… when weather permits will check the fuse box on the trunk. And while waiting for sunshine if i can get my hands on wiring diagram i can check from eCm connector if wiring is short thats causing the o2 to be not operational.
anyone’s help is highly appreciated.
thanks a lot!!!
regards,
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
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From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
This is weird:
downstream O2 sensors failed without fault.
About your boost CEL:
have you inspected the wastegates ?
downstream O2 sensors failed without fault.
About your boost CEL:
have you inspected the wastegates ?
Last edited by CaliBenzDriver; May 13, 2025 at 02:34 AM.
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W213 All-terrain
Not operational does not mean that O2 sensors is defective, more likely are quite very good ....To test the "operational" state, first you have to read and respect the condition from where this reading can be interpreted. Usually something like working temperature, blip throttle, etc...
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@CaliBenzDriver
thanks, indeed it is weird. For wastegate actuation it is moving when activating and deactivating the boost pressure solenoid and it is holding a steady position. Read other posts that a slight bad check valve on a hose can cause under boosts
thanks, indeed it is weird. For wastegate actuation it is moving when activating and deactivating the boost pressure solenoid and it is holding a steady position. Read other posts that a slight bad check valve on a hose can cause under boosts
Out Of Control!!
Joined: Apr 2019
Posts: 11,923
Likes: 6,776
From: Silicon Valley
W212 MY'14 M276-3.5NA @75kMi
@CaliBenzDriver
thanks, indeed it is weird. For wastegate actuation it is moving when activating and deactivating the boost pressure solenoid and it is holding a steady position. Read other posts that a slight bad check valve on a hose can cause under boosts
thanks, indeed it is weird. For wastegate actuation it is moving when activating and deactivating the boost pressure solenoid and it is holding a steady position. Read other posts that a slight bad check valve on a hose can cause under boosts
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@trigital ,
thanks for the additional info will take note of that and run a longer live test. Thats also my thought that O2 are good specially the bank 1 sensor 2 as i recently replaced it with NTK brand after the CAT got damaged when hit by bad transmission shaft. Luckily the connection point of O2 with respect to CAT is minimal but with leak so i went to shop to close the leak by welding it. Its running fine after that and no more CEL. But this time both bank downstream became not operational so i will check again the parameters after checking for fuses and short.
thanks for the additional info will take note of that and run a longer live test. Thats also my thought that O2 are good specially the bank 1 sensor 2 as i recently replaced it with NTK brand after the CAT got damaged when hit by bad transmission shaft. Luckily the connection point of O2 with respect to CAT is minimal but with leak so i went to shop to close the leak by welding it. Its running fine after that and no more CEL. But this time both bank downstream became not operational so i will check again the parameters after checking for fuses and short.
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Thread Starter
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@S-Prihadi ,
thanks a ton for the support in providing related documents. Will share what i find as a forum reference.
thanks,
thanks a ton for the support in providing related documents. Will share what i find as a forum reference.
thanks,
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