DPF P0472 and P0471 No Power/Limp Mode

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P0472 code definition
An exhaust back pressure sensor that is no longer working correctly
The exhaust back pressure sensor is suffering from a poor electrical connection
The exhaust back pressure sensor harness is shorted or open
There is an open in signal circuit occurring between the PCM and exhaust pressure sensor
There is an open between the PCM and the exhaust pressure sensor in the power supply
Short of power to ground in the signal circuit to the exhaust pressure sensor
A faulty exhaust pressure sensor internally shorted to the ground
The PCM has failed internally (this is the least likely reason)
What are the symptoms of the P0472 code?
Lack of power to the engine
Seeing the Check Engine Light come on
A manual regeneration is unable to perform
A crank-no start (if a perform regeneration isn’t able to perform)
How does a mechanic diagnose the P0472 code?
If possible, a PCM flash/reprogram protocol

Checking the exhaust pressure sensor, inspecting its connectors and wiring for rubbing, chafing, burn spots, bare wires, and melted plastic
Taking the connectors apart, inspecting for corroded or burnt terminals and possibly cleaning them
Clearing the diagnostic trouble codes from memory using a scan tool to see if the code returns. If it does, the sensor and various circuits will need to be tested.
Disconnecting the harness that leads to the exhaust pressure sensor with a DVOM (digital volt/ohm meter) and testing the power supply circuit that runs to the sensor to make sure it is powered up.

Common mistakes when diagnosing the P0472 code
The most common reason the P0472 code gets misdiagnosed is because it gets confused with an exhaust gas recirculation code. Even though the exhaust back pressure tube may be found close to the exhaust gas recirculation (EGR) valve, the P0472 code still needs to be diagnosed in a completely different way.

What repairs can fix the P0472 code?
Replacing any damaged wires in the EPS and/or cleaning them
If the connectors were the problem, then erasing the code from memory should result in a clear screen as opposed to the code returning
If the code returns, testing the sensor and its circuits
Checking the voltage of the EPS to see if it has suffered from a failure
Additional comments for consideration regarding the P0472 code
Associated codes like P0471 and especially P0473 may occur along with P0472. They all relate to the same core issue, though, so addressing P0472 should clear out the others too.A P0472 code concerns the incoming signal sent by the exhaust pressure sensor because it's not coinciding with the intake manifold pressure or ambient air pressure. The problem is strictly related to an issue with the electrical circuit. It often occurs with the P0473 code as well.
Disclaimer:

Due to factors beyond the control of Bodgit And Leggit Garage, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. Bodgit And Leggit Garage assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. Bodgit And Leggit Garage recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of Bodgit And Leggit Garage, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained

[simonjenkins]

My Mazda CX5 had a blocked DPF . Mazda main dealer did a regeneration and changed engine oil and filter. Cost £300. A few weeks later DPF warning light came on again. This time the same Mazda dealer said that an exhaust sensor was faulty. Had to wait for two weeks to get new sensor fitted as part needed to be ordered from another country and DPF regeneration again. Another £300. So I am very, very impressed with this video and your skills as a mechanic re finding the cause of the DPF getting blocked. Excellent first class work, if only the garage that I went to was so good. Well done.

[robertmikulinac]

You just uploaded this video in right time, it helped me to solve the issue on 2013 mazda 6. Dealer quoted customer for new dpf however dpf wasn't been blocked in our case it was the exhaust pressure sensor which shorts out when up to temperature and dropping reference voltage causing random fault codes to come on and disturbing communication between control units. Happy to say the upgraded sensor does the job and car is back to life.

[jaapseiye]

I always drove diesels, till i bought a focus 1.6tdi, the hassle was endless ended up scrapping it, so went back to petrol after 25 years for £30 tax car . Nice video Leon

[richardjohn]

love that scan tool, measure pressure with separate tool, excellent idea, would never thought of that, i, just stick to the scan tool live data, now i know what a motionless sensor value means lol, have seen that before as well, and dint know what to do, you have a sharp mind and problem solver, keep up the good work, learn some think every day

[zigzag]

Great job but then again he doesn't need me to tell him that. I just wish he lived on my back step. Because you've got tradesmen that know what to do but cut corners and you the customer wind up paying for it 👍🏿 top job mate

[johnmorton]

Would you care to share your method of cleaning the dpf.

[Rexh_YT]

Excellent video, one very quick question, if there is some exhaust pressure coming out of the exhaust gas pressure sensor tube is it worth cleaning it, if so, what would you use?

[TTRVision]

a word of warning, be aware when testing the exhaust backpressure with that tool.
on similar car I totally destroyed a cheap 1 bar max scale pressure gauge. it went off the scale and turned arround further, the back pressure (and temperature) was insane. if I had tested that with that fancy tool you have, I would need another pressure transducer :)
thanks for sharing, top job!

[mickymac]

I like how you check things rather than just replace parts based on a diagnostic test Leon, too many main dealers do that.What is your favourite make to work on for access and good design.The lad I use loves anything German, hates anything French.

[СергейНеобязательно-зу]

1052mBar is the pressure in my 1.6 citroen. No errors. Car drives absolutely fine. Would you say that it is something with the sensor etc, not DPF? Pressure stays constant at all times, even engine off

[ashy]

Great job once again Leon👍
Stay well everyone 👍
Ash🏴󠁧󠁢󠁳󠁣󠁴󠁿

[CubasAutomotive]

awesome editing. Beautifully done video!.

[leeg]

Hi Leon, love the videos really helpful and always explained well, can i ask what scantool you use, theres loads out there ive tried but that one looks fairly straightforward.

[bcp_towing]

Awesome. Boom. Well thought out and logical explanation thanks Leon. 👍🏽😎

[orourketaxitours]

Excellent job love the detail you go into 👍

[jimbojombo]

Excellent video I have a insignia and been having dpf problems is it true that if I turn my car off while it's doing a regen it dumps diesel into the oil

[johnmorton]

Did you end up doing a couple of regens to get the pressure down to 2 mbar.
I've got one at the moment with the same codes and the same back pressure on idle, this ones only on 63k and just been serviced so I'm happier to regen it once I've sorted the exhaust pressure sensor issue.

[saghirhussain]

what can cause diesel engine with dpf to smoke when engine warm? Dpf is not blocked.I disconnected both dpf sensor pipes and when engine warm it smokes. I disconnected the sensor still smokes when engine warm. it doesn't smokes when engine cold.

[robinwells]

I have a 2011 CRV that I know are famous for dpf issues. I have had a clean done now after two light on limp home episodes. To be fair they were nearly 30k miles apart. Strangely they both occurred in cold conditions after 200 mile blasts up the motorway cruising at 70 mph with cruise control on. On both occasions as I lifted off to come off at my junction the lights have come on. I have had cleans that have resolved the issue the first lasting 30k miles as I say. The second time Honda did a regeneration for me and it lasted only 200 miles and required a second chemical clean.
If as I suspect, it is ash build up and as adblue is urea solution and so acidic, do you think that it would be a good candidate to use to blow into the dpf to fiz away the ash? Is this perhaps the only difference between a dpf and an adblue system?

[zediqbal]

Hi . Just wandering if u have a video of toyota verso. I got diesel n now oil is leaking from some where . Need ur help pls