Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Obscure EGR Fault solved
This saga started with a panic call from my wife when Disco 3 lost power on the return from an airport run. When I eventually found her and plugged in the GAP IID I found a P023-22D fault code, which relates to absolute pressure - turbocharger boost sensor. Engine still ran fine at tick-over but no power.
I had a look under the bonnet and saw a split in the hose between the intercooler and the inlet manifold. I ordered a new silicon hose (and 2 others that come in a Britpart kit), and confidently fitted them. I didn’t do the short one on the turbo itself as it looked pretty tricky to get at and the existing one seemed in good shape. The one on the front right of the engine (facing forward) is easy to replace, the top end of the other is a bit tricky.
Confidently started the car and took it for a test drive – except it had no power and no fault code showing.
So back to square 1 and time to call in Profsr G. He advised checking and cleaning the MAP sensor with brake cleaner, and to check that the turbo actuator arm was working. Did that, still no joy.
Next step was to check and cleaned DPF sensor, which is mounted behind gearbox and can be removed and cleaned with compressed air. Also blew air through the filter itself to check that there was no blockage.
Connected GAP IID in advanced mode and ticked every option there to try to get a reading of a fault code. Eventually got P0401-21(D) exhaust gas recirculation flow insufficient detected.
Profsr G had by then noted that my air flow (9 g/s) at tick-over was low.
Then the Prof suggested blocking off the pipes from the throttle body to the 2 EGRs. There is an easy clip to undo and then the flexible metal convoluted pipe to the EGR can be pulled back to allow the 2p coins (they fit exactly) to be fitted and the pipe and clip replaced.
Air flow was immediately up to 19 g/s from the previous 9.
Did a test run like this and normal service was resumed. After about 5 km it threw another fault code, but that was because the air-flow to EGRs was blocked so I ignored it.
BTW, did you know that English 2p coins are magnetic and Irish ones are not?
So conclusion was that one or both EGR valves was faulty. Disappointing, as both were replaced only 20000km earlier. Checking the invoice confirmed that they were not genuine or OEM but an unbranded part sold by British Parts.
I ordered two new ones – one genuine LR and one OEM from Rimmer’s stock and not that much more expensive than the one supplied by British Parts.
When I removed the RH one I found that the bit of the valve which does the sealing and which should be welded to the shaft that moves forward and back on a lead screw was actually sitting free inside the valve body.
So the valve was trying its best - moving the shaft back and forward but wasn’t actually achieving anything. This explains why there was no proper EGR failure code.
I replace both EGRs, all back to normal. Moral of the story – only buy OEM or original parts.
Thanks to Profs G for his time and patience and many exchanges that pointed me in the right direction.Bentley 8
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3rd Apr 2022 6:10 pm
bensla
Member Since: 02 May 2023
Location: Trowbridge
Posts: 141
Do you know who makes the LR parts?
7th Oct 2023 2:19 pm
French Collection
Member Since: 15 Apr 2020
Location: Aix-en-Provence
Posts: 46
Not sure, but it is not Allparts, possibly Valeo.
If you buy from somewhere like Rimmers they will be able to tell you. You can probably also see on the Auto-doc website.Bentley 8
Rolls Royce Silver Shadow
Triumph Stag
Volkswagen Karmann Ghia Razor Edge
Jaguar XJC
Jaguar E-type
Jaguar XK8
Land Rover Discovery 4
Mercedes E350
Ford Granada 2.8 Ghia X
Ford Granada 2.8i Ghia X
7th Oct 2023 3:32 pm
PROFSR G
Member Since: 06 Mar 2017
Location: Lost
Posts: 4678
The electronic elements were originally manufactured by the French electronics manufacturer Sagem. I don't know if the made the body as well but I'm inclined to doubt it.yµ (idµ - eAµ) ψ=mψ
7th Oct 2023 6:00 pm
bensla
Member Since: 02 May 2023
Location: Trowbridge
Posts: 141
Interesting thanks. I have a Valeo item on now which apparently was new about 12k miles ago and is now jamming open. Wondering what the best brand to buy is for its replacement.
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