Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail

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Tue 18 May 2021 21:57
Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail - Eddm87

Hi,
Took my scenic 1.9 dti for a diagnostic as there is a real loss of power and the ‘preheat’ warning light is on also.
Got told 2 glow plugs are bad and a mass air flow sensor fault is showing.

since then I have changed all glow plugs, removed and cleaned egr valve (which was stuck) and removed and cleaned the air flow sensor (was clean anyhow, used correct non contact spray etc)
However, problem is still there, I read that the fault can clear if you pull the electrics from the maf, which I did, warning light still on.

I think it is a lack of air/fuel consumption. Is my best bet to buy a new maf? I have heard this needs to be genuine part also? Or by pulling the electrics out and the fauls still occurring show that it’s not the maf?

thanks in advance.
Edd
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Tue 18 May 2021 22:45
Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail - bathtub tom

The glow plugs won't affect the loss of power after the first few seconds of running.

How does it run if you disconnect the MAF plug?

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Tue 18 May 2021 23:48
Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail - Eddm87
Thanks for reply, I didn’t expect glow plugs to alter performance but needed doing anyhow.

It drives exactly the same with the maf disconnected, still with warning light on also.

Thanks
Edd
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Wed 19 May 2021 01:53
Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail - elekie&a/c doctor
Really need to check any live from the maf sensor to see if there is any fluctuation in voltage under differing engine load . Also check for any air leaks on the intake system , to turbo, inter cooler etc .
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Wed 19 May 2021 08:10
Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail - Railroad.

The fault code relating to the Mass Air Flow sensor is where the fault is being reported from. This is not necessarily what the problem is. This is where so many people go wrong. The ECM cannot determine the difference between a sensor giving a low reading because it's faulty or a sensor giving a low reading when it's actually telling the truth when something else is wrong.

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Sat 22 May 2021 20:57
Renault scenic 01 plate - Renault scenic 1.9 dti mass air flow sensor fail - Eddm87
Thanks for replies, I appreciate and agree with all.
I couldn’t test the maf as didn’t have the equipment to hand.
Closing up this thread, I bought a new maf and the fault cleared. Also found a leak before the maf and that the air intake filter was knackered. These were obviously fixed and it drives much better now. Behind the maf was a linkage on the air line which I couldn’t get moving, freed it up though.
Anyone reading this thread with a similar issue, I advise to clean the maf sensor and take out and clean the ecg as (after much research) if this is out of action, also shows this fault.
Thanks all
Edd
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