P0234 / P0471 Error 2012 ML350 Bluetec
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Joined: Aug 2016
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From: Massachusetts USA
2012 ML350 Bluetec
P0234 / P0471 Error 2012 ML350 Bluetec
2012 ML350 Bluetec Diesel (OM642)
After completion of Oil/water cooler replacement and clearing all errors codes using MB Star diagnosis tool, the car started the car and ran for couple of hours.
No issues at idle condition. On raising the accelerator, there seems to be exhaust fumes coming from underneath engine bay and following error codes:
P0471: Exhaust Pressure Sensor A Circuit Range/Performance
P0234: Turbocharger/supercharger overboost condition
The upper limit value of component B60 (Exhaust Back Pressure sensor) has been exceeded
There is an internal fault in component B60 (Exhaust Back Pressure sensor)
Two items I am not sure of that is contributing:
1) I replaced the clamp on the pipe fitting downstream from Turbo to catalytic converter but DID NOT replace the crush washer at that junction. That could be leaking. I will replace with new washer. Also there are no blockages anywhere from Turbo to DPF.
2) I replaced the Fuel Rail Pressure sensor (A0071534328) on EGR that I broke. (Driver side, next to EGR)
Other than that, there are no leaks or issues.
Anyone, please let me know whats the reason for "Exhaust back pressure exceeded".
Also does the turbo get really hot when you step on the gas pedal for some time ? I read somewhere that turbo can reach upto 1050 Deg Cent.
Also I am not able to reset the "Low Coolant level Message" on the dash. How do I perform ? could there be air trapped in the circuit as I drained out all the coolant ? and how do I remove if I had to do that ?
Please help. Thanks.
After completion of Oil/water cooler replacement and clearing all errors codes using MB Star diagnosis tool, the car started the car and ran for couple of hours.
No issues at idle condition. On raising the accelerator, there seems to be exhaust fumes coming from underneath engine bay and following error codes:
P0471: Exhaust Pressure Sensor A Circuit Range/Performance
P0234: Turbocharger/supercharger overboost condition
The upper limit value of component B60 (Exhaust Back Pressure sensor) has been exceeded
There is an internal fault in component B60 (Exhaust Back Pressure sensor)
Two items I am not sure of that is contributing:
1) I replaced the clamp on the pipe fitting downstream from Turbo to catalytic converter but DID NOT replace the crush washer at that junction. That could be leaking. I will replace with new washer. Also there are no blockages anywhere from Turbo to DPF.
2) I replaced the Fuel Rail Pressure sensor (A0071534328) on EGR that I broke. (Driver side, next to EGR)
Other than that, there are no leaks or issues.
Anyone, please let me know whats the reason for "Exhaust back pressure exceeded".
Also does the turbo get really hot when you step on the gas pedal for some time ? I read somewhere that turbo can reach upto 1050 Deg Cent.
Also I am not able to reset the "Low Coolant level Message" on the dash. How do I perform ? could there be air trapped in the circuit as I drained out all the coolant ? and how do I remove if I had to do that ?
Please help. Thanks.
Last edited by jeevankrish; Jan 18, 2018 at 10:22 AM.
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Joined: Sep 2015
Posts: 2
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2012 ML350 Bluetec
RE: P0234 / P0471 Error 2012 ML350 Bluetec
Hello,
I am experiencing the exact same issue, on my 2012 ML350 Bluetec. Same two codes, seems to be in "limp mode" or at least a very low power condition as well. Did you find out what the problem was? Any help would be greatly appreciated. Anything I can do to avoid taking it to the dealer would make me very happy.
Thanks,
Mark
I am experiencing the exact same issue, on my 2012 ML350 Bluetec. Same two codes, seems to be in "limp mode" or at least a very low power condition as well. Did you find out what the problem was? Any help would be greatly appreciated. Anything I can do to avoid taking it to the dealer would make me very happy.
Thanks,
Mark
