Having had a couple of yellow DPFs warnings recently (which I cleared by going for a drive), I got one straight to red the other day. “DPF Full. Go to a dealer”. Or similar. Engine de-rated (ie went into limp mode).

Having an extended warranty I called them and a very capable LR Assist chap turned up and I chatted to him.

Things I thought were interesting were:

1. They can force regen the DFP by plugging in while moving and this will fix the vast majority of such problems. Not mine though.

2. LR say it’s OK to drive on red. They knew I had a 200 mile journey to get home. It will regen on its own in a red state but will not clear the fault or re-rate though. Or so we thought.

3. Mine not only de-rated but ran on for about 5 seconds after being turned off. He’d never seen that before. Nor the widely inconsistent soot figures the car was producing. (Varied between 15 and 32g).

4. He spent about 90 minutes trying everything he could think (including telling it it had a new DPF) but he couldn’t clear the fault. Never seen that before apparently.

5. The DPF system does work by post-ignition diesel injection so these cars (mines a 2014 VSE 4.4, no adblue) do suffer from oil dilution. My service symbol had just come on and his laptop said it had a 9% dilution (Service Required is triggered at 7%). He had seen nearly 40% dilution in other cars!

6. Bizarrely, my car cleared its own red DPF warning later in the day on its own and re-rated the engine back to full performance. That wasn’t supposed to be possible.

I’ll get the DPF cleaned for peace of mind and keep my fingers crossed.

This post just FYI really to add to the list of experiences with these machines......

Wow interesting MacPaul.

I wonder about the cause though... Look for any soot around any air system / inlet hose. This might explain your weird restricted too.

Air leaks = soot production.

Air leaks can also throw a restricted but not an error code.

These DPF's definitely live in a dark arts world.

How many miles has your car done?
Reason I ask is because, over time ash builds up in the DPF.
Soot can be incinerated in the regen process but not ash.

This could explain why it wouldn't clear (but did in the end, weird). If it's ash then after a regen your pressure differential voltage is more than say 0.8 or 0.9v generally, meaning your DPF is too blocked.

Last thing I wanted to mention is to avoid those on-car cleaning methods. The only way to properly clean is to take it off the car and put it in a 'flash' type machine. Big machines can take a reasonable length of pipe with the DPF.


. Cheers, Greg
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2011 Vogue SE 4.4 with lots of toys in Stornaway

Have an oil change ASAP. This allowed me to clear a red warning - my oil dilution was 12!! Your wildly varying readings lead me to think it’s a sensor problem. Poss change for a new sensor and see if any difference?

Hi Greg,

The car’s done 59,000 miles.

No soot or oil mist anywhere (the guy checked) and no air leaks (ditto). You’re right though, a leak does lead to effective overfuelling as the map sensor under-reads and too much fuel is injected.

The ash is usually expelled by the exhaust gas flow, but I thought the same thing, hence plan plan for a DPF clean.

Thanks for your interest!

Simon

The sensor thought occurred to me too but the tech said if sensor(s) had failed there’d be a message on his machine.

They’re continually checking for ‘impossible’ mismatch between the voltage outputs of the two sensors and if one arises, a fault code is stored.

Given the other weirdness, he thought there was some strange combination of inputs to the Powertrain Control Module/engine ECU that was causing it to misdiagnose what it thought was wrong.

Given the previous yellow warnings though, it sounds like the DPF may not be clean, so I’ll get it washed out.

Off-vehicle ultrasonic sounds like the best method as far as I can see.

One other interesting thing he told me was that the EGR is involved in the regen process.

It moderates the amount of clean air going into the system and hence the burn temperature of the DPF regen.

Right, just had my car back from the LR dealer having had a red dpf light come on and not able to clear - had rear sensor replaced. They couldn’t force regen the dpf (they got lower soot readings but the engine Ecu failed to recognise the lower reading and it remained in restricted power with red light on.)

LR dealer suggested getting the dpf cleaned to get a soot reading lower than 28.5 so they could force regen (£95 a pop + vat)

Took it to a terraclean franchise (performance engineering company) who did it for £180 + vat. They also cleared all the red lights and had the soot level down to 1.9g of soot. it has run fine since and soot levels rose to 5.99 over the next 20-30 miles but had a motorway run for 50 miles the other day and plugged the IID in for the trip. The car started doing its own regens along the way at around 350 degrees so it’s back to normal operation again (was failing to initiate Normal regens before)

Click image to enlarge

Click image to enlarge

I've had the RR (3 litre TDV6 2014, 115k km 72k miles) for 3 weeks now - and yesterday afternoon it went direct to Red DPF Full warning coming home through town. I didn't have time to go for a drive on the motorway immediately, so came home then went out 30 minutes later - in Limp mode I have an older Autel MaxiDAS 708 so plugged that in to see what I could find and found the Special Function menu in the PCM Module menu and was able to force a Regen.

I drove to 100m from the on-ramp to the motorway, started the process - showing 36 grams of soot (!!) and set off down the motorway at 100kph on the cruise. Soot level started reducing after 5 minutes and then completed when it went below 6 grams.

All good.

I have a replacement Android 10.25 headunit fitted (from AndroidAftershock which is awesome) so bought the Torque Pro app and have an OBDII wifi dongle so thought I would set up Torque to show the DPF temperatures and pressures - and maybe also soot level.

But - no luck. The car's ECU only shares a small set of PIDs to the Torque app - and none of them are DPF, exhaust temp or pressure related.

I've searched the inter web and can't find any RR specific PIDs for the Torque app anywhere - apart from OldJaguar.com who have some for transmission and rear differential temperatures.

Has anyone got the PIDs that would allow me to programme Torque? Much easier to check on the headhunt every couple of weeks than to drag out the Autel unit and plug it in....

Thanks

John