M272 - intake leak, manifold leak or o2 sensor failure (P0942 & P0230).
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2008 W204
M272 - intake leak, manifold leak or o2 sensor failure (P0942 & P0230).
Just had the engine mounts on my 2008 C300 4matic replaced at 98,000 miles by an indie.
He said he had to "remove the exhaust" in order to complete the job, I'm guessing the manifold.
A few days after the job, I took it work... on the way there it was running very sluggish, and it stalled in the parking lot.
Drove it home and checked the codes...
I got a
0942 - "the efficiency of the right catalytic converter is insufficient."
0230 - "due to a possible leak in the intake air system, an implausible signal was received from oxygen sensor 1 (cylinder bank 1)."
I cleared the codes, and took it for a drive - it was back to normal.
I have been continuing to drive and for the most part it is fine - although I do often notice a rough idle at stop lights.
The 0230 (leak in intake cylinder bank 1) continues to reappear after long but not short trips... the 0942 catalytic code has not come back.
I am hoping this is just the O2 sensor... but the code is throwing me... it is suggesting an air leak, which would be possible if the exhaust was not put back properly.
With this given info, what would you guys think is the most likely actual fault here? I think it is possible a bad o2 sensor (perhaps sabotaged or broken by the indie) could cause this... or perhaps he did not put the exhaust on correctly and there is a leak after the intake... otherwise I cannot possibly see how this could be an intake leak, the indie did not mess with the intake and its too coincidental for a fault to show up right after the mounts were replaced. Firstly, can a bad 02 sensor cause a catalytic converter fault?
He said he had to "remove the exhaust" in order to complete the job, I'm guessing the manifold.
A few days after the job, I took it work... on the way there it was running very sluggish, and it stalled in the parking lot.
Drove it home and checked the codes...
I got a
0942 - "the efficiency of the right catalytic converter is insufficient."
0230 - "due to a possible leak in the intake air system, an implausible signal was received from oxygen sensor 1 (cylinder bank 1)."
I cleared the codes, and took it for a drive - it was back to normal.
I have been continuing to drive and for the most part it is fine - although I do often notice a rough idle at stop lights.
The 0230 (leak in intake cylinder bank 1) continues to reappear after long but not short trips... the 0942 catalytic code has not come back.
I am hoping this is just the O2 sensor... but the code is throwing me... it is suggesting an air leak, which would be possible if the exhaust was not put back properly.
With this given info, what would you guys think is the most likely actual fault here? I think it is possible a bad o2 sensor (perhaps sabotaged or broken by the indie) could cause this... or perhaps he did not put the exhaust on correctly and there is a leak after the intake... otherwise I cannot possibly see how this could be an intake leak, the indie did not mess with the intake and its too coincidental for a fault to show up right after the mounts were replaced. Firstly, can a bad 02 sensor cause a catalytic converter fault?
Last edited by LandSeaAir; Aug 27, 2017 at 04:54 PM.
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Joined: May 2022
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2014 c63
Just had the engine mounts on my 2008 C300 4matic replaced at 98,000 miles by an indie.
He said he had to "remove the exhaust" in order to complete the job, I'm guessing the manifold.
A few days after the job, I took it work... on the way there it was running very sluggish, and it stalled in the parking lot.
Drove it home and checked the codes...
I got a
0942 - "the efficiency of the right catalytic converter is insufficient."
0230 - "due to a possible leak in the intake air system, an implausible signal was received from oxygen sensor 1 (cylinder bank 1)."
I cleared the codes, and took it for a drive - it was back to normal.
I have been continuing to drive and for the most part it is fine - although I do often notice a rough idle at stop lights.
The 0230 (leak in intake cylinder bank 1) continues to reappear after long but not short trips... the 0942 catalytic code has not come back.
I am hoping this is just the O2 sensor... but the code is throwing me... it is suggesting an air leak, which would be possible if the exhaust was not put back properly.
With this given info, what would you guys think is the most likely actual fault here? I think it is possible a bad o2 sensor (perhaps sabotaged or broken by the indie) could cause this... or perhaps he did not put the exhaust on correctly and there is a leak after the intake... otherwise I cannot possibly see how this could be an intake leak, the indie did not mess with the intake and its too coincidental for a fault to show up right after the mounts were replaced. Firstly, can a bad 02 sensor cause a catalytic converter fault?
He said he had to "remove the exhaust" in order to complete the job, I'm guessing the manifold.
A few days after the job, I took it work... on the way there it was running very sluggish, and it stalled in the parking lot.
Drove it home and checked the codes...
I got a
0942 - "the efficiency of the right catalytic converter is insufficient."
0230 - "due to a possible leak in the intake air system, an implausible signal was received from oxygen sensor 1 (cylinder bank 1)."
I cleared the codes, and took it for a drive - it was back to normal.
I have been continuing to drive and for the most part it is fine - although I do often notice a rough idle at stop lights.
The 0230 (leak in intake cylinder bank 1) continues to reappear after long but not short trips... the 0942 catalytic code has not come back.
I am hoping this is just the O2 sensor... but the code is throwing me... it is suggesting an air leak, which would be possible if the exhaust was not put back properly.
With this given info, what would you guys think is the most likely actual fault here? I think it is possible a bad o2 sensor (perhaps sabotaged or broken by the indie) could cause this... or perhaps he did not put the exhaust on correctly and there is a leak after the intake... otherwise I cannot possibly see how this could be an intake leak, the indie did not mess with the intake and its too coincidental for a fault to show up right after the mounts were replaced. Firstly, can a bad 02 sensor cause a catalytic converter fault?
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2010 E-350/2009 ML 550/2012 C300
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E550 Coupe 2wd (2016)
I think if the ex were put back wrong you'd hear it. And I'd imagine it would need to be a pretty big leak for the ECU to sense it. So I would suspect they left the O2 wires connected and lowered the ex, which may have broken a wire?
The plugs for my O2's are so hard to reach that I can't even touch them, and even when I lowered my ex to do my mounts they were still in the "too hard" category. So if they're like mine I can pretty much guarantee they did not unplug them.
spoken; you said you installed new sensors and still have the code? What code exactly? The internet says P0230 is fuel pump
The plugs for my O2's are so hard to reach that I can't even touch them, and even when I lowered my ex to do my mounts they were still in the "too hard" category. So if they're like mine I can pretty much guarantee they did not unplug them.
spoken; you said you installed new sensors and still have the code? What code exactly? The internet says P0230 is fuel pump
