JustCarsForum - Your Ultimate Automotive Community

Greetings everyone,

I now own a 2013 W204 C250 CDI (204 BHP) equipped with an OM651 engine.


I aimed to compose a piece due to the scarcity of knowledge on the topic, believing it would assist in addressing any concerns that individuals may be experiencing.

Backstory: While driving home, I had an abrupt loss of power while speeding on the road. It seemed to be in a kind of limp mode, as the kickdown function was inoperative and the engine speeds did not exceed 3000 rpm. Upon decelerating, the gear transitions were markedly abrupt and conspicuous. I restarted the vehicle, and thereafter, everything returned to normal. No EML was shown on the cluster. The codes were scanned, revealing the following error code:

P0248-72 - Malfunction detected in Output 2 of the low-pressure turbocharger. The actuator fails to shut.

Possessing practical experience with automobiles, I first conducted a vacuum test on the turbo actuators to verify the functionality of both actuators on the OM651 Bi-turbo. Both actuators maintained vacuum, allowing me to rule it out as a problem.

My subsequent task was to conduct a smoke test on the vacuum lines, since a leak in the vacuum system has been documented to impact the turbo vacuum. No anomalies were detected during the smoke test.

I then searched the internet for further information on the issue and, to my astonishment, I encountered an essay from many years before that was pretty challenging to comprehend.

The following components were directed to be replaced, since a user experienced the same error code that I encountered. The part numbers are shown below:
Turbo Boost Pressure Transducer - A0091533128 – OEM Supplier Pierburg 7.00782.12.0, about £40 from GSF's eBay.
Vacuum Control Solenoid – A0025407097 – I opted for the Pierburg 7.02256.37.0, which cost around £35 on eBay.
Both components are located in the front of the engine, above the auxiliary belt, and are straightforward to repair. If anybody need further information on the placement of these pieces, please do not hesitate to contact me, and I would be pleased to help. Their location may be determined by identifying the vacuum lines at the front that connect to the actuator under the air box.

It has been around two weeks, and the automobile is operating flawlessly without any more troubles. I hope my essay may assist others, since I was impeded by this difficulty for an extended while.

Thank you for your write-up. I have been intensely struggling to identify this problem for the last month.

I am experiencing the same error code, with no EML light on, and the vehicle enters limp mode. Power it down and restart, and it will return to regular functionality.


It occurs sometimes, and at other times, it is quite OK, irrespective of whether I am driving aggressively or not.

I will proceed to replace the two components you recommended. I presume the problem has not recurred.

Could you assist me in determining the position and the method of fitting? Is it feasible for do-it-yourself implementation?

Here are the URLs for the two portions; could you verify their accuracy? I have attempted to replicate your stuff using copy and paste.

We apologise for the disruption... (gsf ebay)

We apologise for the disruption... Euro vehicle parts on eBay

It is a 2013 C220d model.

Greatly appreciated

Thank you so much - I had been rather distressed about the matter. I modified the first section two weeks before, however continue to get analogous concerns. I will modify the second half and provide input. I have replaced many components to no avail. Nevertheless, the vacuum control solenoid has not been replaced. I will get the component and replace it.

Thank you, regrettably, I changed both components and was unsuccessful. Continues to malfunction, particularly at speeds over 80 km/h. I have undergone a transformation.
1. Wastegates A and B
Boost Pressure Transducer

Vacuum Control Valve
Four map sensors, quantity two


I have exhausted all options. There are no leaks; I am uncertain as to why this occurs.

Have you inspected your diesel particulate filter? It may be full.

It is often preferable to get a diagnosis from an expert. Conserves time, money, and reduces stress.

The hoover mechanism is straightforward to inspect. I would also do a smoke test.

Thank you for this. I verified and rectified the DPF issue. The blockage of the DPF resulted in the mistake. I am now receiving the P0299 error code, indicating progress.

It is important to note that the two map sensors I replaced were Bosch boost sensors instead of OEM boost sensors. Enquire if OEM would surpass aftermarket Bosch sensors in real specifications. It seems plausible that this may be the problem.

Comprehensive smoke testing completed with no leaks detected.