Hi Guys,

 

After timing belt change i have some issues with the car O3 RS TDI. After i start it and do a couple of accelerations the power goes down, like a limp mode. I run a test with VCDS and found DPF Differential Pressure Sensor P2456 fault.

 

I read about some issues with a pressure sensor G450. 

 

Is there anyone else witch had this issue ?

This morning i’ve double checked the sensor and i saw something strange. It seems that a tube is missing. See attached. I can’t find if this is how it should be for my engine CUPA.

 

 

I have a feeling that's normal.

Yeah that's normal, they used to have another pipe running to them. The differential pressure sensor measures the exhaust pressure before and after the DPF. Seeing as the pressure after the DPF is comparable to atmospheric pressure anyway, it was somewhat redundant. As it was more likely the line would freeze or block and then cause an issue, it was removed.

That’s good news !!! Thanks guys. I will replace the sensor then and try to recalibrate + force regeneration. I hope this will solve the issue. 

 

I will keep you updated

Mine failed right after the 210k km service (with timing belt change).

Interestingly there was no warning light on the dash but it definitely went into some kind of limp mode because I felt like I lost 100 HP.

When I arrived home I did a scan with VCDS, saw the fault code, checked the sensor...and it was melted badly with a hole through it, and the heat shield was black from the escaping exhaust gases.

By the way my colleague's car did the same at almost the same mileage.

 

Looks like your sensor also started to melt...?

 

Pictures of my failed sensor: http://forum.index.hu/Article/viewArticle?a=146776943&t=9029418

Edited 19 September, 20196 yr by aki78

Yes Aki, no warning light and limp mode after timing belt change. Mine has 134k km. Will change it today. 

 

You had any issues with calibration after replacing it ? 

Dealer replaced it not me (company car).

I am still wondering why does it fail after timing belt change...?

Mine was the same after a timing belt change. Thought it was a coincidence!

 

If you look at the video below in the comments section there are a few people who had the same issue after a belt change:

 

https://www.youtube.com/watch?v=5v23gN1VSi0

I’m back and it seems that i am cursed.

 

During my trip towards the service, the DPF regeneration began. I said ok nice, its been a while since the last one. I decide to go 2 extra km am 3000 rpm so i can complete the regen. 

 

I was 500 m away from the service when i received warnings and my car went into a bad limp mode. After i’ve opened the hood i saw the sensor completly melted. See attached...

 

Now i need also a new cable to connect my new sensor. I’ve managed to save the tube.

 

Be very careful with this !!!

Bloody hell!

WTF have you done!!!

 

was it a knock off sensor?

 

My guess is that you had a leak and you managed to get a flow of hot exhaust gasses which has cremated the sensor

Edited 19 September, 20196 yr by SuperbTWM

That's exactly what happened to mine.

 

The wiring is all part of the main engine loom so the affected part can't easily be replaced.

 

I ordered part no. 8K0973703 from TPS.

 

I hope that after the new sensor and the above part will mounted i will not have the same issue. 

 

I am not sure what caused this. I believe the sensors are crap and if they are not recalibrated after belt change, this happens.

The sensor part no. has been revised at least once so I believe the fault lies in the sensor. I still can't get my head around the link to the timing belt!

45 minutes ago, jordy_wd said:

The sensor part no. has been revised at least once so I believe the fault lies in the sensor. I still can't get my head around the link to the timing belt!

 

Does it have to be removed as part of the job, and maybe the hose clamps are not tight enough after re-use, allowing hot exhaust gas to bypass the sensor?

Edited 19 September, 20196 yr by micro

I’ve checked with the mechanic who changed the timing belt and he said that he didn’t touch the sensor. Now, who knows...

 

It’s also interesting that my engine among with others only have the left hose. But it seems that this is the new design.

You're lucky that didn't start a fire - that is a bit of a safety issue IMHO.

Yes it is. I’ve heard about BMWs on fire due to issues like this one.

 

I have the new sensor and now i am waiting for the other part (cable). 

 

After the fix i’ll update you.

 

Anyone knows if it needs a recalibration from VCDS or it’s plug and play ? I don’t want the same issue to happen again and hope that the root cause was this faulty sensor.

7 minutes ago, Roby10 said:

Yes it is. I’ve heard about BMWs on fire due to issues like this one.

 

I have the new sensor and now i am waiting for the other part (cable). 

 

After the fix i’ll update you.

 

Anyone knows if it needs a recalibration from VCDS or it’s plug and play ? I don’t want the same issue to happen again and hope that the root cause was this faulty sensor.

 

Yes it needs a recalibration using VCDS.

Now i have the replacement parts.

 

Need to mount them + recalibration

23 minutes ago, Roby10 said:

Now i have the replacement parts.

 

Need to mount them + recalibration

 

Were you able to see which wiring goes to each pin? If not I can take a photo of mine for you.

Same thing happened to me few days after belt change.. Probably after first DPF regen.

 

 

Hi Guys,

 

I was able to splice the wires. I took a photo before to see how they were wired and also checked a friends car. Example attached (not mine)

 

Starting from the top:

Yellow+Grey;Brown;Yellow+Brown 

 

Today i will try to do the calibration using VCDS

 

 

What an absolute crap plastic design. Chocolate teapot springs to mind. Obviously manufacturers were aware of the risks having put a feeble cover over it.