Afternoon All,

I've started getting an intermittent engine warning light appearing associated with fault codes P0172 & P0175, indicating that the system is running too rich on Bank 1 and Bank 2. I've re-set the light on a number of occasions but it eventually comes back on. This is sometimes accompanied with a reluctance to start (low revs) but can appear whilst on the motorway.

I've cleaned out both mass flow air sensors and purchased a second hand one off eBay to test the operation. no matter what I do with the air flow sensors, it doesn't seem to keep the problem at bay.

I've pulled the live data from the car and included this in the photographs below. The only things of note that I can immediately see are that the voltages for both mass flow air sensors is very different between both banks (-30.82 v on Sensor 1 and 1.25 V on sensor 2). This voltage readout doesn't change when I swap the mass flow air sensors around so i'm wondering if these are just normal readings. The only possibly thing that I can think of is that there is a small nick out of the plug wires for the nearside air sensor. I thought that this was bank 2, so it wouldn't explain the very low voltage associated with sensors 1 which, from what I've read is the offside sensor.

In terms of the live data, the only other reading that I thought looked a bit off is the "Long term secondary oxygen sensor fuel trim - bank 1" is returning a value of 0%, where Bank 2 is returning -0.78 V.

Anyway, i'd be much obliged if anyone could take a look at the reading below to see if they notice anything immediately off. The car seems to run fine with no smoke or noticeable power loss. Vehicle is a 2010 5.0 Supercharged for reference.

Cheers,

Tom

Hi,

I've left the car with the garage for a couple of weeks and they've come back suggesting that the issue is most likely the cats. Has anyone ever had experience of these codes being associated with the cats?

Since my previous post, i've looked at some more live data and looks like the fuel rail pressure is quite high at 6809 kPA. The short and long terms fuel trim values also seem quite far apart. Could these be explained by the cats?

Any thoughts would be most appreciated.

Thanks

Hi,

Just bumping this back up to see if any clever people out there might be able to shed a light on this? No further information to report other than the garage fitted a new purge valve. Couple of days later, the same codes tripped the check engine light, but after around three days the light went out by itself.

Cheers

Hey, did you ever figure this out? I’m also getting those codes. TIA

Don't hold your breath, tpeat12 hasn't posted in 2 1/2 years...

I would say first thing to check is battery voltage and condition....

A dealer may be able to pull off some codes which may help.... Pete
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@Haylands, thanks. I have a GAP tool so I can pull codes. I did quite a bit of work recently (cleaned intake valves, MAF sensors, throttle body, and intake gaskets. I'm hoping that does the trick. But we'll see.

@Ekshamp

I purchased tpeat12's car and fixed this issue after a bit of a troubleshooting process.

Long answer is here: https://www.fullfatrr.com/forum/topic65565.html

Short answer, I replaced both HPFPs as they were leaking fuel into the oil & the fumes were being put back into intake via the PCV and causing the codes. There is a video in the topic above that explains it quite nicely.

Hope this helps.