slaurro

Hi there!

I had some problems with my 2009 C250 CDI. The DPF was clogged so i went to a tuning company and had it removed.

The problem is i`m still getting P0471: Exhaust Pressure Sensor Range/Performance. I used to get it before i removed the DPF as well.

I get the fault code only in the morning. First drive seems ok, but if i stop the engine before it gets warm and start it again after a couple of minutes the car goes into limp mode. I have an ODB, i scan the code... P0471.

If i don't stop the car until the engine gets to optimum temperature (about 15 minutes), there are no problems, it doesn't get into limp mode if i stop and start it again.

My catalytic converter is still on the car... Is there any chance that it is clogged resulting in a high pressure on the exhaust? If so, wouldn't the car show any other symptoms? And would it only cause problems when cold? Is there any way i can test and see if my cat is clogged?

Apart from that, i can't see why i would get P0471... maybe the sensor itself is faulty. Does anyone know the part number for the sensor or where it is located? I googled around and i found two types of sensors: exhaust pressure sensor and differential pressure sensor. Are they the same? If not, which one do i need?

Thanks alot!

slaurro

I think the differential pressure sensor was disconnected when i had the DPF OFF. So i guess the p0471 fault code refers to Exhaust Back Pressure sensor B60? Anyone knows where that is?

Carsy

You might receive more help from the UK website. Not much diesel experience here.

My engine is a 646 so cannot help.

400ixl

When you say you had it removed? Do you mean they removed the DPF and fitted a straight through pipe?

If so, did they also remap the DPF and EGR out of the system? If not it will cause issues like you have described.

slaurro

They only removed the ceramic out of the metalic case and refitted it on the car. They said they disconnected the sensor which triggered the regeneration of the DPF. I'm guessing that's the differential pressure sensor. So... I think my problem is the EBP (Exhaust back pressure) sensor... I wanna clean it but i have no clue where that is...

400ixl

That doesn't sound right with every other car I have seen have this process done.

You don't normally disconnect any sensors. In the ECU map you reconfigure the car to delete the DPF regeneration settings and the EGR recirculation.

I would check with a competent remapper that the process has been done correctly as it doesn't sound like it has.

Someone like www.gadtuning.co.uk would know.

slaurro

Maybe... but given that i had this issue before the DPF off... i think it's not related.