Exhaust manifold pressure sensor - P0471
- Thread starter HITECH
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HITECH
Active Member
Majority of people with this fault get confused with dpf sensor and exhaust back pressure sensor. I have done a few cars with this fault that came from other garages and they changed the dpf sensor and NOT the faulty exhaust pressure sensor. One the 2.1/2’s tgere is 1. On the bigger engines there are 2.
Go simplify this. The dpf sensor is a black plastic sealed unit 2 pipes clamp onto usually on drivers side of the emgine at the back (UK). The exhaust pressure sensor is NOT a catalyitic O2 srnsor in the exhaust either. It is a spark plug like similar part that is screwed into the EGR exhaust line passenger side of bonnet. Only reason im giving this info is i have come across people changing dpf sensors or catalytic O2 sensors because they associate EXHAUST PRESSURE SENSOR in the actual exhaust when that is NOT actually the location for this part. Just a little heads up on it.
Go simplify this. The dpf sensor is a black plastic sealed unit 2 pipes clamp onto usually on drivers side of the emgine at the back (UK). The exhaust pressure sensor is NOT a catalyitic O2 srnsor in the exhaust either. It is a spark plug like similar part that is screwed into the EGR exhaust line passenger side of bonnet. Only reason im giving this info is i have come across people changing dpf sensors or catalytic O2 sensors because they associate EXHAUST PRESSURE SENSOR in the actual exhaust when that is NOT actually the location for this part. Just a little heads up on it.
OneForTheRoad
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I keep hearing about a tiny hole on the end that gets blocked , I couldn't see such a hole ,just the obvious hole at the end. .
Hi Guys,
I have a A180d 2015 and its throwing up P047195 - Exhaust Back Pressure Sensor 1 Has A Malfunction. The Mechanical Setup is Not Ok.
My vin is WDD1760122V086494.
Any advice/part no/part location would be appreciated.
Thank you xx
I have a A180d 2015 and its throwing up P047195 - Exhaust Back Pressure Sensor 1 Has A Malfunction. The Mechanical Setup is Not Ok.
My vin is WDD1760122V086494.
Any advice/part no/part location would be appreciated.
Thank you xx
15yemenroad
New Member
Hello, I know this is an old thread but I was wondering if anyone was still able to help please.
I have a P0471 - Exhaust gas pressure sensor - range/performance problem
I have a knowledge of how exhaust systems work, but on this 2.1 Mercedes I’m confused. I’ve already replaced the two DPF pressure differential sensors for another fault code, but every time I search for the exhaust pressure sensor, I don’t find anything. I can see something resembling a pressure sensor near the top - front of the engine but it doesn’t show in any catalogs I can find online.
Hopefully someone can help please , many thanks
I have a P0471 - Exhaust gas pressure sensor - range/performance problem
I have a knowledge of how exhaust systems work, but on this 2.1 Mercedes I’m confused. I’ve already replaced the two DPF pressure differential sensors for another fault code, but every time I search for the exhaust pressure sensor, I don’t find anything. I can see something resembling a pressure sensor near the top - front of the engine but it doesn’t show in any catalogs I can find online.
Hopefully someone can help please , many thanks
OneForTheRoad
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Send me the vin , I'll have a look 4u
15yemenroad
New Member
OneForTheRoad
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I can only see 2 sensors listed as ' pressure ' on the engine side
One is for fuel and the other is a glow plug pressure sensor., I've no idea what that's meant for
You do however have 2 dpf type sensors as part of your exhaust system.
One is this as described in the picture, the other is
A 007 153 60 28
Last edited:
OneForTheRoad
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A0071536028 is listed as
Description:
Pressure differential 17 KPA. Particle filter. So I'm thinking the one in the photo is more of back pressure sensor and not dpf related as such.
Description:
Pressure differential 17 KPA. Particle filter. So I'm thinking the one in the photo is more of back pressure sensor and not dpf related as such.
15yemenroad
New Member
I can only see 2 sensors listed as ' pressure ' on the engine side
One is for fuel and the other is a glow plug pressure sensor., I've no idea what that's meant for
You do however have 2 dpf type sensors as part of your exhaust system.
One is this as described in the picture, the other is
A 007 153 60 28
View attachment 164875
15yemenroad
New Member
lol a glow plug pressure sensor?! I can’t even pretend to know what that would do. Thanks for your help I’ve replaced them both from Mercedes already.
This been bothering me for a few weeks now, I’ve got a basic obd2 reader but need a scanner to see what readings I get…. Might just take this sensor out and replace it.. see what happens.
This been bothering me for a few weeks now, I’ve got a basic obd2 reader but need a scanner to see what readings I get…. Might just take this sensor out and replace it.. see what happens.
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OneForTheRoad
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Is that the front of engine ,right side ??
15yemenroad
New Member
Correct it is. A more expanded view.
I’ve had EGR replaced, those DPF sensors you mentioned replaced, the actuator which snapped (by blue arrow, common apparently) Now I’m on the last code and I’m stuck.
other problems which I hope all linked are the temp gauge on the dash almost never reachers 90c usually hovers about 50c, fuel consumption has gone up and exhaust stinks of diesel on tickover. Contemplating blanking EGR off but not sure of legalities of it. I just want it fixed lol
I’ve only had it a year and don’t I’ve ever had it running at full power, so any help is appreciated
Last edited:
15yemenroad
New Member
So. Just unplugged that sensor and it came up with the following faults
P0470 - already active
P0472 - only appears when sensor unplugged
So, that is indeed, the exhaust pressure sensor.
Why it doesn’t show up in parts catalogs is very odd.
I’ve tested continuity between all the pins in the sensor and none buzzed, not sure they are supposed to as I don’t have any drawings but tomorrow I shall remove it and try and retrieve a number and order a new one.
P0470 - already active
P0472 - only appears when sensor unplugged
So, that is indeed, the exhaust pressure sensor.
Why it doesn’t show up in parts catalogs is very odd.
I’ve tested continuity between all the pins in the sensor and none buzzed, not sure they are supposed to as I don’t have any drawings but tomorrow I shall remove it and try and retrieve a number and order a new one.
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HITECH
Active Member
Yes it is the exhaust gas pressure sensor. Compketely different from a DPF sensor. People even start mentioning DPF sensors only add confusion to this shen their is none. The part number is actually stamped on the exhaust gas pressure sensor . I had to replace mine on my w03. When they go faulty they give you a limp (with full revs) which is even more confusing. In other words your turbo gets disabled but still have full rev range. I done various tests on this fault with the faulty exhaust gas pressure sensor in and out with new one with live recordings simply because i had to know the nature of the fault and also the other false codes it causes aswell along the line.
Take it out get part number off it n replace.
15yemenroad
New Member
I’ve seen you mention this a few times lol, but I definitely replaced right sensor, I only know this as I replaced both a few months ago for a DPF fault. I’ve replaced exhaust pressure sensor A0009052706.
Fault codes erased and stays off during 20 min road. Problem sorted.
Now my boost disappears within a few mins, with no fault codes. Messed around with my diagnostic app and it states boost pressure failed a test, but gives me no more information.
Need a better app I suppose.
HITECH
Active Member
When you say boost goes. are you meaning your into limp mode with no codes?
15yemenroad
New Member
Correct yes, took it for a drive and noticed it mainly when I boot it in sports mode, it reaches 7th gear and then disappears and goes into eco mode. No fault codes. I will be trying to test for air leaks tomorrow.
I have a reader that allows me to track sensors. Anyone know what the reading for boost should be. Im currently using the car car scanner app on iPhone. Is there a better one for reading data?!
HITECH
Active Member
Outa curiosity when you replaced the DPF sensor was it a genuine one, how much?
15yemenroad
New Member
I didn’t know which one was causing the fault, so replaced both. One was around £90 and one was around £70 from Mercedes. I have the invoice somewhere so will post part numbers and cost when I can.
One is at back on bulkhead passenger side, and the other is under the air intake/air filter. I mention for people who can’t find them it took mEva long time to find that one. And the clips for the pipes going to/from them ain’t the easiest to undo either.
