P0471 error Code

[robbie74]

my 2010 e350 diesel is throwing up error code p0471.

It did this a while back so i changed the pressure sensor https://media.autodoc.de/360_photos/.../h-preview.jpg & it fixed the problem for about 6 months, now 1 month ago the same error has come back.
Ive replaced it yet again but the error will not go , do you think its likely i got a dodgy one ?
do you think its Exhaust back pressure sensor ?

when i clear the codes the car runs fine for 2 or 3 starts , then it goes into what sounds like regen mode with reduced power , then next start up the check engine light comes on & stays on & it seems to stay in regen mode with reduced power until i clear codes again .

thanks

 

[Jobsworth]

What you linked in your first post is the DPF differential pressure sensor. The exhaust back pressure sensor is something different, located near the EGR valve. When you remove the sensor carefully have a poke in its hole because soot often blocks the passage up to where the sensor screws in.

 

[robbie74]

i am thinking to replace the Exhaust back pressure sensor next , does that sound like it could be the issue ?

Should i try having a poke down the hole see if its clogged first ?

 

[W1ghty]

i am thinking to replace the Exhaust back pressure sensor next , does that sound like it could be the issue ?

Should i try having a poke down the hole see if its clogged first ?

I spray mine with carb cleaner every year , you will see the hole after that .

 

[robbie74]

cleaned out the hole & cleaned the inside of the sensor , still the same .
I disconnected that sensor & it gave me more error codes so i presume its working ?

Any other ideas ?

 

[W1ghty]

cleaned out the hole & cleaned the inside of the sensor , still the same .
I disconnected that sensor & it gave me more error codes so i presume its working ?

Any other ideas ?

New sensor ?

 

[robbie74]

New sensor ?

if its giving me error codes when I disconnect it would it not give me the same error codes if it was not working ?
When connected it's p0471 , disconnected it's p0472

 

[W1ghty]

if its giving me error codes when I disconnect it would it not give me the same error codes if it was not working ?
When connected it's p0471 , disconnected it's p0472

Maybe it’s not fully working ?

 

[Supernoodle]

if its giving me error codes when I disconnect it would it not give me the same error codes if it was not working ?
When connected it's p0471 , disconnected it's p0472

No. Sensors have electrical diagnostics and plausability diagnostics.

You had a P0471 Exhaust Pressure Sensor “A” Circuit Range/Performance. That's checking if the measured value falls within an expected range.

P0472 is Exhaust Pressure Sensor “A” Circuit Low, this means it's seeing 0v, which would only happen if there is a short to ground or open circuit. Either way, it won't run plausability diagnostics as there's no point.

So the implication is that ECU is seeing a signal, but it's not correct. You have to detemine if it's due to external factors like the blockages other mentioned or if it is just faulty.

 

[robbie74]

No. Sensors have electrical diagnostics and plausability diagnostics.

You had a P0471 Exhaust Pressure Sensor “A” Circuit Range/Performance. That's checking if the measured value falls within an expected range.

P0472 is Exhaust Pressure Sensor “A” Circuit Low, this means it's seeing 0v, which would only happen if there is a short to ground or open circuit. Either way, it won't run plausability diagnostics as there's no point.

So the implication is that ECU is seeing a signal, but it's not correct. You have to detemine if it's due to external factors like the blockages other mentioned or if it is just faulty.

Ive ordered the Exhaust back pressure sensor , hopefully it sorts it. Will update once installed

 

[robbie74]

Received the part today , 2 minute install & all fixed .
Thanks ppl for your help.

For future ref for anyone, this is the part i ordered that fixed it

https://www.autodoc.es/ridex/15233867