P0470 MIL (G450 Pressure Difference Sensor)

yaminator · Feb 5, 2013

New member here, but have been a lurker for a few years now. 56K miles on the JSW now, and just about out of warranty.

Issues seen so far have been:
@ ~12K, gas door would not open. Replaced under warranty.
@ ~20K, HPFP failure, <50mi after 20K service completed at the dealer.
Potentially, the fuel pump was not primed properly, or just coincidence. Repaired under warranty.

MIL popped up and error code scanned was P0470.

001136 - Exhaust Pressure Sensor 1 (G450)
P0470 - 000 - Malfunction - Intermittent
Freeze Frame:
Fault Status: 00100000
Fault Priority: 2
Fault Frequency: 15
Mileage: 90939 km
Time Indication: 0
Date: 2100.14.16
Time: 10:30:13
Freeze Frame:
RPM: 1150 /min
Speed: 50.0 km/h
Temperature: 10.8°C
Temperature: 70.2°C
Temperature: 66.0°C
Pressure: 326 mbar
Pressure: 3 mbar

Datalogged what I am assuming is the G450 sensor, and did not see any abnormalities. Perhaps the logging rate (turbo enabled) is not high enough to pick up the erroneous value(s) that caused the MIL. I'm assuming the first "Pressure" value in the freeze frame is the pressure difference, and the second "Pressure" value is the pressure difference offset. Not really sure what the pressure difference offset is, but those were the only pressure related variables in VCDS. This is a big assumption though...

Cleared the code, and took a quick drive. The MIL did not light up, but when checking for fault codes, the same error had already been logged.

Ordered a new sensor (076-906-051-B), replaced, and completed adaptation. Easy access and <30mins to replace and adapt the new sensor.
No MIL has occurred since replacement, but will continue monitoring.

Datalogged after sensor replacement and its basically the same thing, acceleration causes higher deltaP, cruising gives a ~constant deltaP, idle has low deltaP. Potentially if I left the faulty sensor in longer before replacement I would see more obvious symptoms (abnormal soot load, regen based on time or distance), but it was replaced <20 mi after MIL. I could not tell any difference in the way the car drove with the MIL on.

Datalog of "Bad" sensor

Sensor Adaptation procedure.

yaminator · Feb 7, 2013

Uggg, MIL came back. Same code. Any ideas?

DZL_Damon · Feb 7, 2013

You 100% you swapped out the correct differential pressure sensor? It's a long shot since it looks like you know what you are doing, but there are 2. The G450 and G505: http://audi.workshop-manuals.com/a3-mk2/index.php?id=2487

Also.. you didn't crack that little plastic barb like I did... did you?

yaminator · Feb 7, 2013

DZL_Damon said:
You 100% you swapped out the correct differential pressure sensor? It's a long shot since it looks like you know what you are doing, but there are 2. The G450 and G505: http://audi.workshop-manuals.com/a3-mk2/index.php?id=2487

Also.. you didn't crack that little plastic barb like I did... did you?

Okay, I feel dumb now. I didn't crack the barb, but as soon as I saw your link, I knew I replaced the wrong sensor. Incidentally, the original G505 sensor I removed was exactly the same part number as the new one received by the dealer. The original G450 sensor in my car was 03G-906-051G, and per the web known to be faulty.

The sensor has been replaced and adapted and will provide feedback if the problem has been resolved.

Picture below to clarify the location of the sensors.

yaminator · Feb 8, 2013

DZL_Damon said:
You 100% you swapped out the correct differential pressure sensor? It's a long shot since it looks like you know what you are doing, but there are 2. The G450 and G505: http://audi.workshop-manuals.com/a3-mk2/index.php?id=2487

Also.. you didn't crack that little plastic barb like I did... did you?

And I forgot to thank you for pointing it out, so thanks!

DZL_Damon · Feb 8, 2013

Wow, I almost didn't comment because I thought I'd sound like a tool and you appeared to know what you were doing already. I'm happy a smoking gun was found! Hopefully that's it.... did you throw away the old one?

yaminator · Feb 8, 2013

DZL_Damon said:
Wow, I almost didn't comment because I thought I'd sound like a tool and you appeared to know what you were doing already. I'm happy a smoking gun was found! Hopefully that's it.... did you throw away the old one?

I'm personally too thick skinned to get offended, especially over the internet. And if I can't find a direct solution to my problem, I like to thoroughly document it for myself and others in the future. Appreciate your help.

I do complete all service/repairs on all our cars.

BTW, I still have the old sensor. Bad habit, but I usually wait at least 6 months (if ever) before throwing out old parts. Do you want it cracked open or electrically tested for FA?

DZL_Damon · Feb 10, 2013

yaminator said:
BTW, I still have the old sensor. Bad habit, but I usually wait at least 6 months (if ever) before throwing out old parts. Do you want it cracked open or electrically tested for FA?

Ha... I do the EXACT same thing. I forgot the sensors were different, figured you could use it on the right location. Nevermind. Hope you got it solved now.

yaminator · Feb 2, 2014

To close the loop, MIL has not turned on since replacing and adapting the correct sensor. Now at ~65K miles.

Alec · Feb 9, 2014

Thanks for this useful post!

I'm in the middle of the same thing on my wife's car. I just replaced the wrong sensor.

CJAA engines have the sensors just as you show them.

I got confused, because the CBEA engines have the G450 sensor mounted where the G505 is on the CJAA's and the the G451 where the G450 is. I looked at the wrong diagram in the pdf file, but didn't realize it until I read this!

Thanks again,
Alec

sfpegasus · Mar 24, 2014

Well, mine went south last friday. 33,300 mi on the car, but outside the 3yr/36K warranty.
Dealer claims it's a $400 repair job. (seriously?) "Not under the emissions warranty" they said. A simple phone call to WV customer care fixed that - 100% warranty coverage to be performed wednesday.

Thanks for the excellent write up. The photos are a great help too.

sfpegasus · May 19, 2014

Just a followup to the above post. Dealer successfully convinced VW that BOTH the G505 and G450 sensors were bad, even though they failed to remember I have VCDS and can generally diagnose these problems myself. They replaced the (properly working) G505 sensor with an improper part (snork!). They failed to secure and shield the new G450 sensor properly. The left off parts that secure the G505 sensor because they put the hose clamps on wrong and the retaining clamp wouldn't fit properly. And then they had the audacity to tell me I was wrong and that the parts were never on the car, despite photos I took before this whole process began.

It took four trips total. I ended up buying the parts on ebay and properly securing the G505 sensor myself.

This is not the first time I have had a dealer misrepresenting warranty repairs to VW. It seems to be a game they play and I'm running out of options for dealers I can trust.

JSWTDI09 · May 19, 2014

One little note for others with this same issue. The 2009 (CBEA) engine and the 2010+ (CJAA) seem to have these sensors backwards. The one you marked as G450 is G451 on an'09 and the one you marked a G505 is G450 of an '09. This is why many shops just change both sensors at the same time instead of risking changing the wrong one. I have seen several of these sensors fail and it is always the one right above the DPF that fails (no matter what it is called). I suspect that it the heat of repeated regenerations that kills this sensor. So far, I have never seen the one over the Aux Fuel Pump fail. Also remember that most '09s use the -A sensor whil all 2010+ TDIs use the -B sensor. The -B sensor will work on both engines, but you must replace both sensors if you change from the -A to the -B sensor. You cannot have one of each in the same car.

Have Fun!

Don

sfpegasus · May 21, 2014

Apparently my dealer didn't get that memo and replaced the G505 (the one over the aux pump - working properly, as you indicate) with a -A sensor, requiring yet another trip when the check engine light came on.

Morons.

Both sensors are now -B.

michaelquerty · May 22, 2014

I have a 2009 with exhaust pressure sensor 2 fault, I am also debating on getting a DPF delete and Malone stage 2, do have to have these sensors if I get the tune/delete?

'10TDI · Aug 2, 2014

I had the "emission system malfunction' come on in my 2010 Jetta TDI. I did some troubleshooting and found it is the G451 sensor that is bad (the one located behind the oil fill neck, covered by a heat shield). I bought a new sensor and am trying to get the old one out, but am having a heck of a time getting the two rubber hoses off - any tips on how to do that? Also, is it difficult to get the new sensor in once the old one is out? I'm trying to figure out if I can do this myself or if I need to take it in to the dealer. I don't want to end up with a bigger problem than I started with. Thanks for any input.

NWwash · Aug 4, 2014

I've read the threads on the P0470 codes and see that VCDS is needed to start the new G450 sensor. However, some people seem to have skipped that step.
Is it possible to successfully replace this sensor without the VCDS S/W start-up?
Thanks, Chris (2010 Jetta TDI, 82k)

JSWTDI09 · Aug 4, 2014

NWwash said:
Is it possible to successfully replace this sensor without the VCDS S/W start-up?

This probably depends. If the new sensor's behavior is nearly exactly the same as the old one, you might get lucky and it will work right out of the box. You can probably use a generic OBDII scanner to clear the fault code. In the worst case, you could replace the sensor and see what happens. If the fault code comes back - you need to find someone with VCDS to do the adaptation. If the fault code does not come back, you are probably OK. In other words - its a coin toss. It might work and it might not work. Are you feeling lucky?

Have Fun!

Don

NWwash · Aug 6, 2014

Don, thanks for the encouragement; bought the sensor yesterday and installed it today!
Tried a key on-key, off cycle three times in hopes of triggering a re-calibration; erased the code and then drove for 20 minutes per the Ross-Tech recommendation (70C coolant, >40 MPH, 2000-2500 RPM, 10-15 min). After shutting the car off, the fans came on which I have always assumed meant that it had been in a regen cycle. After 5 more short drive-cycles the light is still off!
Finger crossed, Chris

NWwash · Aug 7, 2014

'10TDI said:
I bought a new sensor and am trying to get the old one out, but am having a heck of a time getting the two rubber hoses off - any tips on how to do that?

I don't think I could have removed the old sensor's clamp without a set of 11" long needle nosed pliers with bend tips. Also, I pressed down on the clamp with a screwdriver (using my other hand) while holding the clamp open. Another set of hands would have been useful. Only the larger hose has a clamp, maybe that is the high pressure side?
A little water on the new sensor tubes seemed to help installation as others have suggested. I was worried about using anything except water for fear of contaminating the sensor. It is a pain, but take your time, Chris

mkvme · Aug 11, 2014

2010 CR cjaa, I would want the sensor directly behind the oil fill cap right? Its all wrapped up in a blanket? I cant seem to find the part online if someone could help me with a source id be thankful. Its not the one connected to 2 hoses correct? Just has one connector in it? P0470

JSWTDI09 · Aug 11, 2014

mkvme said:
2010 CR cjaa, I would want the sensor directly behind the oil fill cap right? Its all wrapped up in a blanket? I cant seem to find the part online if someone could help me with a source id be thankful. Its not the one connected to 2 hoses correct? Just has one connector in it? P0470

The sensor you describe (behind the oil fill cap and wrapped in a blanket) is the one that usually fails. However, once you unwrap that blanket, you will discover that it also has 2 hoses and an electrical connector. The sensor in that blanket is actually the exact same part as the one above the aux fuel pump (which is easier to see and easier to get at). The part number for your car is: 076 906 051 B. Unsnap that blanket and unhook the sensor but be careful, the bracket thing that holds this sensor is easy to break. I know a guy who broke his and the new sensor is held in place with some safety wire now. Anyway, the hardest part is getting at the hose clamps. A variety of odd shaped pliers can be an asset.

As to source, any VW dealer should have it in stock. Go online to the dealer's website and look for a parts link. Many dealers have "on-line" prices that are cheaper than if you just walked in and asked for the part. I know of several dealers with online prices under $100 for this sensor. The only Florida dealer I know anything about is Gunther VW in Coconut Grove (wherever that is). Their online price is: $98.90 (plus tax, I assume).

Have Fun!

Don

mkvme · Aug 12, 2014

Thanks for the detailed reply. I looked at both sensors and the one above the oil fill only had one plug in it, and didn't have two hoses like the other one. This is what's confusing me. Is it further down? Because going by the picture of the sensor locations this is what I found

mkvme · Aug 19, 2014

Thanks again jsw for the reply, I re read it and found there are in fact two hoses attached. Replaced this last night. That clamp was a biotch, and then the hoses were really stuck on there. Hopefully I'm all set now, thanks for all the info everyone. This thread is a good one

Sent from my iPhone using Tapatalk

GDM · Jan 11, 2015

Replace one or both sensors?

My MIL came on last week, so I grabbed logs and it shows 2 Faults Found - P0472 and P0471:

001138 - Exhaust Pressure Sensor 1 (G450)
P0472 - 000 - Signal too Low - MIL ON
Freeze Frame:
Fault Status: 11100000
Fault Priority: 2
Fault Frequency: 148
Reset counter: 255
Mileage: 77454 km
Time Indication: 0
Date: 2015.01.01
Time: 18:09:22

Freeze Frame:
RPM: 2047 /min
Speed: 55.0 km/h
Temperature: 2.7°C
Temperature: 65.7°C
Temperature: 54.0°C
Pressure: -218 mbar
Pressure: -3 mbar

001137 - Exhaust Pressure Sensor 1 (G450)
P0471 - 000 - Implausible Signal - MIL ON
Freeze Frame:
Fault Status: 11100000
Fault Priority: 2
Fault Frequency: 4
Reset counter: 255
Mileage: 77473 km
Time Indication: 0
Date: 2015.01.04
Time: 09:15:34

Freeze Frame:
RPM: 2231 /min
Speed: 87.0 km/h
Temperature: 7.2°C
Temperature: 73.8°C
Temperature: 72.0°C
Pressure: -218 mbar
Pressure: -3 mbar

Both seem to indicate G450 is having trouble, but I've been reading this and other threads re: these sensors, G450 and G451 or whatever... Question is, should I just replace G450 (076 906 051B) or should I replace both that and G451 (1K0 131 552B) at the same time? G450 lists ~$100 while the other one lists at ~$200.. I suppose I could replace the cheaper one first and see if it fixes stuff... ?

Thoughts?

JSWTDI09 · Jan 11, 2015

GDM said:
Both seem to indicate G450 is having trouble, but I've been reading this and other threads re: these sensors, G450 and G451 or whatever... Question is, should I just replace G450 (076 906 051B) or should I replace both that and G451 (1K0 131 552B) at the same time? G450 lists ~$100 while the other one lists at ~$200.. I suppose I could replace the cheaper one first and see if it fixes stuff... ?

Thoughts?

Both sensors are p/n 076 906 051B. That other p/n is the sensor PLUS the metal bracket it mounts to. You do not need that bracket (I have never heard of one failing). You can replace 1 and then do the adaptation. If the fault comes back, take the one you removed and try it in the other place. There is some confusion (and possible differences between 2009 and 1010+ years) as to which sensor is which. This confusion is why many mechanics just replace both at the same time because this always works the first time and they are not too expensive.

In my limited experience (only 3 cars), it is always the sensor above the DPF that fails, not the one over the aux pump that is much easier to replace. I suspect that heat is a factor in the failures.

Have Fun!

Don

FXDL · Jan 3, 2016

I have a 2010 Jetta TDI and I got the P0470 code.
So on the 2010 which one is what, as it is a little confusing?
Sounds like a good idea to just change both but what is the PN's for them?
One must have them reprogrammed?
Vw up here wants $227.00 each for them!!!
Confused.

JSWTDI09 · Jan 3, 2016

FXDL said:
I have a 2010 Jetta TDI and I got the P0470 code.
So on the 2010 which one is what, as it is a little confusing?
Sounds like a good idea to just change both but what is the PN's for them?
One must have them reprogrammed?
Vw up here wants $227.00 each for them!!!
Confused.

Wow, it might be worth buying them in the US and paying for shipping, or maybe you are pricing the wrong part. The p/n is: 076 906 051 B for the sensor alone and in the US the MSRP is $105 and online prices range from $65-$90 (in US dollars). After replacing the sensors you should use VCDS to "adapt" them (this basically means you tell the ECU that it has new sensors and it "learns" how they work). It only takes a few seconds, but it does require VCDS.

Have Fun!

Don

FXDL · Jan 4, 2016

Thank-you for the info. I am pricing else where for them.
I got the P0470 code and reads on my tester Exhaust pressure sensor A circuit.
I assume the A is #1 sensor?
Where is the location as it seems to me there is a bit of confusion on which is what between the two?
Thanks again eh.

FXDL · Jan 7, 2016

Got the new sensor for some $85.00. Both are the same PN at VW now so I have been told.

P0470 MIL (G450 Pressure Difference Sensor)

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