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Benzio

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Hello.

I'm wondering if anyone could help me with a problem I'm having.
I've tried to search all over the Internet and I can't seem to find a definitive answer.

I have a Mercedes A class 2018 with 46k miles on it, the engine light came last Thursday.

I took it to a few garages, one said it was a dpf sensor and the other said it wasn't. The fault reading is " P3005E7: communication with soot particulate sensor is faulty " I haven't lost any power and everytime the fault is cleared, it come on the next day....

Would anyone what this means because I'm confused.
 

LostKiwi

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From the code description I'd go with the first garage.
 

mioba

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LK knows his stuff. Dont use a run of the mill garage, use a MB indy. they are aquainted with the brand the quirks.
 
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Benzio

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From the code description I'd go with the first garage.
Thanks for replying..
The first garage was halfords, they said it was a DPF sensor and the second garage said the dfp sensor is working fine which was weird so I booked the car in with a mercedes indy specialist on Tuesday.... hopefully it won't cost me a kidney after they've diagnosed it
 
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Benzio

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LK knows his stuff. Dont use a run of the mill garage, use a MB indy. they are aquainted with the brand the quirks.
I've booked it in with an MB indy on Tuesday, I'm hoping it's only a dpf sensor ( fingers crossed) not too expensive.
 

mioba

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Like any car, they throw a code when there is a fault. I would not say common as you cant predict a fault
 
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Benzio

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Like any car, they throw a code when there is a fault. I would not say common as you cant predict a fault
Your right, I guess for me it's the first time an engine light has came on so that's why I was asking.
 

LostKiwi

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Mercedes do record everything going on so fault codes are common but often don't cause an issue. Some errors self clear after certain parameters are met.
Whenever I buy a Mercedes the first thing I do is read and clear all codes.
Then I can worry about only those that come back.

Where are you based? There are Indy's and Indy's....
 
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Benzio

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Mercedes do record everything going on so fault codes are common but often don't cause an issue. Some errors self clear after certain parameters are met.
Whenever I buy a Mercedes the first thing I do is read and clear all codes.
Then I can worry about only those that come back.

Where are you based? There are Indy's and Indy's....
Im based in East Manchester.. It's weird because since the engine light came on, my fuel consumption has increased, I'll lose 3 or 4 miles just sitting at traffic lights or maybe I'll drive a mile and I'll 4 miles.

Is the Soot particulate sensor, part of NOX sensor and if that's faulty does it increase the fuel consumption?
 

LostKiwi

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Ok. Here's how it works
You have a diesel engine.
One of the byproducts of diesel combustion is soot. Soot is extremely bad for health and can contribute cancers and other lung diseases.
To reduce soot manufacturers fitted a diesel particulate filter to trap the soot particles inside the exhaust system. When the filter gets full enough the engine generates additional heat in the DPF to turn the soot to ash (which is kept in the DPF). This process is called a regen. The ash takes far less space than soot so the DPF can store a lot more of it.
If for any reason the DPF cannot regen it will eventually block up.
One of the things that stops a regen is a fault that turns on the engine light. Your car is in this state. Your DPF is filling up more and more and if not fixed will eventually get to the point the DPF cannot ever be regenerated.
Now as your car is running with a fault it will default to running in a safe mode limiting power and increasing consumption as it's no longer running optimally.
If the DPF is also blocked it will increase the effort the engine has to make to clear exhaust gases.

In short yes it will have less power and use more fuel and if left too long will cost a lot more to fix
 
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Benzio

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Ok. Here's how it works
You have a diesel engine.
One of the byproducts of diesel combustion is soot. Soot is extremely bad for health and can contribute cancers and other lung diseases.
To reduce soot manufacturers fitted a diesel particulate filter to trap the soot particles inside the exhaust system. When the filter gets full enough the engine generates additional heat in the DPF to turn the soot to ash (which is kept in the DPF). This process is called a regen. The ash takes far less space than soot so the DPF can store a lot more of it.
If for any reason the DPF cannot regen it will eventually block up.
One of the things that stops a regen is a fault that turns on the engine light. Your car is in this state. Your DPF is filling up more and more and if not fixed will eventually get to the point the DPF cannot ever be regenerated.
Now as your car is running with a fault it will default to running in a safe mode limiting power and increasing consumption as it's no longer running optimally.
If the DPF is also blocked it will increase the effort the engine has to make to clear exhaust gases.

In short yes it will have less power and use more fuel and if left too long will cost a lot more to fix
Thanks Mate, this made more sense than half the things I read on the Internet... I've got the car booked in at a MB Indy's for Tuesday, once they diagnos the fault properly. I'll get it booked to get the fault fixed ( fingers crossed it ain't a big job )
 

LostKiwi

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If you're lucky it will be the differential pressure sensor. About £30 for a Bosch sensor and under an hour to fit.
 
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Benzio

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If you're lucky it will be the differential pressure sensor. About £30 for a Bosch sensor and under an hour to fit.
Hopefully.... For some reason and I could be wrong, I'm thinking it might be a o2/soot sensor just because of the fault code description "soot particulate sensor faulty" or could this also mean differential pressure sensor fault hmm
 
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supernoodle

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I don't know that fault code but the DPF differential sensor is an analogue device and directly wired to the PCM. The Particulate Matter Sensor communicates to the PCM over CAN bus.
They don't use the word communicate for items directly wired, just stuff on CAN, LIN, SENT.
P3xxx codes are for auxiliary emission devices too. So Benzio, I suspect your hunch is right.
 
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Benzio

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I don't know that fault code but the DPF differential sensor is an analogue device and directly wired to the PCM. The Particulate Matter Sensor communicates to the PCM over CAN bus.
They don't use the word communicate for items directly wired, just stuff on CAN, LIN, SENT.
P3xxx codes are for auxiliary emission devices too. So Benzio, I suspect your hunch is right.
I'll have to wait and see what the MB indy garage says on the Tuesday... I spoke to another MB indy garage today after describing the fault code.. he also seems to think its a pressure sensor without a diagnostic its hard to tell. Hopefully his right about the pressure sesnor because a nox/o2 sensor costs more than an arm and a leg without the labour charge.
thanks for replying mate.
 

supernoodle

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PM sensor is not the same as NOx sensor. It's another seperate sensor.
 
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Benzio

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PM sensor is not the same as NOx sensor. It's another seperate sensor.
I didn't know that... out of curiosity, is a PM sensor expensive ?
 


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