Exhaust back pressure sensor pipe blocked

[chloemp]

Hi. Wondering if anyone can help. My engine management light came on my Mercedes a class a180 CDI. I went for a diagnostic said it was the exhaust back pressure sensor. I managed to change the pressure sensor myself but noticed that the pressure sensor pipe wasn’t letting any air flow flow through once being tested. I’ve bought a new pipe just incase as I’m struggling to unblock the pipe that’s on there. I've tried heating it up and sticking thin wire through but it seems very clogged. Any suggestions as garages are unable to fit me in for weeks just to look at it. Also it’s impossible to undo the bolt to change the pressure sensor pipe!

 

[Oleks1992]

Hi. Wondering if anyone can help. My engine management light came on my Mercedes a class a180 CDI. I went for a diagnostic said it was the exhaust back pressure sensor. I managed to change the pressure sensor myself but noticed that the pressure sensor pipe wasn’t letting any air flow flow through once being tested. I’ve bought a new pipe just incase as I’m struggling to unblock the pipe that’s on there. I've tried heating it up and sticking thin wire through but it seems very clogged. Any suggestions as garages are unable to fit me in for weeks just to look at it. Also it’s impossible to undo the bolt to change the pressure sensor pipe!

Just replace the pipe for the sensor, very common problem and never exhaust backpressure sensor

 

[OneForTheRoad]

No pipes on an exhaust back pressure sensor , only an electrical connection.

Your messing about with the dpf pressure sensor .

 

[Trickythemerc]

I think the OP may be talking about the pressure differential sensor ?

 

[Oleks1992]

No pipes on an exhaust back pressure sensor , only an electrical connection.

Your messing about with the dpf pressure sensor .

There is pipe for backpressure sensor as its a renault engine OP is talking about, they're common to block up with carbon

 

[OneForTheRoad]

There is pipe for backpressure sensor as its a renault engine OP is talking about, they're common to block up with carbon

Oh sorry , I'm not on any Renault forums , can't help . I'm only familiar with this sensor .

 

[OneForTheRoad]

And this sensor , no pipes on either . Not rubber ones anyhow.

 

[Oleks1992]

Oh sorry , I'm not on any Renault forums , can't help . I'm only familiar with this sensor .

View attachment 151939

That's the sensor that's on renault engined mercedes and there is a pipe going to it. The sensor below usually just screws into egr housing

 

[HITECH]

That's the sensor that's on renault engined mercedes and there is a pipe going to it. The sensor below usually just screws into egr housing

why do peple always mixup the diffirence between a dpf pressure sensor and an exhaust back pressure sensor.
Yes diffirence is the DPF sensor has 2 pipes going to it. An exhaust back pressure sensor usualy screws into EGR housing before it hits the EGR. I repeatedly have had to replace exhaust pressure sensors ( which screw in like a spark plug) after a customer has had a previous garage replace the DPF sensor.
The diagnostic codes are completely diffirent but im assuming when some mechanics from older cars hear exhaust in the diagnostic code they assume either an o2 sensor or a dpf sensor. Us ut something to do with newer cars and EGR valves AND dpfS I DUNNO. This confusion continues to go on. Does my head in !

 

[Oleks1992]

why do peple always mixup the diffirence between a dpf pressure sensor and an exhaust back pressure sensor.
Yes diffirence is the DPF sensor has 2 pipes going to it. An exhaust back pressure sensor usualy screws into EGR housing before it hits the EGR. I repeatedly have had to replace exhaust pressure sensors ( which screw in like a spark plug) after a customer has had a previous garage replace the DPF sensor.
The diagnostic codes are completely diffirent but im assuming when some mechanics from older cars hear exhaust in the diagnostic code they assume either an o2 sensor or a dpf sensor. Us ut something to do with newer cars and EGR valves AND dpfS I DUNNO. This confusion continues to go on. Does my head in !

Yeah I know right some people just can't or can't be bothered to trace where the pipes go to. On newer fords dpf sensor only has 1 pipe going to it for example. And on the renault 1.5 dci engines that are in mercs exhaust backpressure sensor has a single metal pipe going to it which always blocks up. And on dpf sensor there are 2 pipes which are at the back of the engine. But yeah on om651 and om642 both backpressure sensors just screw into the egr housing