The Dreaded Engine Warning Light

[SaracensBD]

Help, please! It's a 2008 Ducato 2.3 multijet 130. The engine warning light is on on the dash. Plugging in the device to read the OBD shows two faults:

• P0111 Intake Temperature Sensor 1 Circuit Range / Performance
• P0101 Mass or Volume Air Flow A Circuit Range / Performance

I fiddled with some wires under the bonnet and reset the faults. The engine warning light stayed off for one trip but then returned. There didn't seem to be any dropoff in engine performance.
Also, the rear reversing light isn't working. There is no power to it when in reverse.
My suspicion is a wiring or connector problem under the bonnet but I would welcome any advice that you knowledgeable people may have.

 

[TerryL]

You are describing the exact symptoms I had on my 2007 2.3 multijet i.e. the same model. Resetting the engine fault worked for maybe two trips but came back. Garage said all sorts of (expensive) things but were reluctant to work on it although they did "tighten up the airbox inlet retainer clip" which didn't appear to help. So then, after the recent long layoff and more in hope, I reset it it again and - no more engine light!

During lockdown the service/MoT garage had told me the reversing lights weren't working (still passed though) so at the same time as I did the last engine reset I had a mooch round and found a blown reversing light fuse, which I replaced.

Now you'll all say no possible connection - but I don't believe in coincidence!

 

[Happy Jim]

Some MAFs have the IAT sensors combined which would give the symptoms above. I’d swap the MAF if it’s the normal plug in type (£30ish)

Jim

 

[Grummyb]

Wht do people say rear reverse light because I've never seen a front reverse light

 

[TerryL]

Now this is interesting and maybe can save a few folk many hundreds of pounds.

I'm here at the Peterborough Show and decided to have the engine remapped by Quantum, who have a stand here. Whilst he was doing his thing I just happened to mention the weird solution to the engine warning light fault - and he said, yes, that's quite correct! Huh?

Turns out that the power supply to the MAF sensor comes from the reversing light circuit! He discovered this whilst trying to find a sensor fault, found a blown fuse and the fault went away. But not content with just "finding" it, he actually investigated the wiring to discover this seemingly absurd fact! On the vehicle he was checking, chafing had caused the wires to short where the harness came out of the chassis extension, blowing the fuse.

So to anyone who is having this fault show up on the diagnostics, do a check for blown fuses first - ANY blown fuse. You may very well save yourselves many hundreds of pounds by "experienced" technicians just replacing expensive parts - "'cos that's what the computer says".

So Barry Miles have you checked and found the same as me?

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[SaracensBD]

Brilliant! I checked fuse F35 and it was blown, so I replaced it and reset the faults. The reversing light is working and the engine warning light is out.
Thanks, TerryL

 

[Happy Jim]

Blimey, that is mental - great info TerryL

 

[Fattrucker]

Hi folks .

The first search I have done of the forum has brought me here .
I have similar issues to SaracensBD and TerryL .
I have the dreaded P0101 and P0111 error codes .
This is on my 2008 2.3 Multijet 120 with 219,000miles on the clock .
I did a little digging and found fuse F35 (7.5A) was blown .
Replacing it did get the radio working but not the reverse light .
Nor did it alleviate the P0101 or P0111 codes .
This was before and after a brand new MAF sensor was bought and fitted .
It was a Bosch purchased from GSF for the princely sum of ONE HUNDRED AND TWELVE whole English pounds !!!
Ouch ! Double ouch when I found it didn't cure the issue .
The connector looked fine when I fitted it and there didn't appear to be any corrosion that I could see.
The wires are as you might expect on a 2008 van . Showing their age , and a little worse for wear .
I'm certainly not the first person to have had a poke around under the bonnet .
As evidenced by copious amounts of electrical tape and numerous snapped clips under the bonnet .
The van runs at reduced power levels but does not have any warning lights illuminated on the dash .
I highly suspect the bulb has been removed to be honest.
The symptoms first appeared driving up a steep(ish) hill at around 50mph .
Where there was a sudden loss of power and I had to stir the gearbox vigorously to coax the van to the summit , cresting at around 30mph.
There are no undue or excessive emissions when driving .
Idling is fine as is starting the van from hot or cold .

Any further insight you guys could share on these errors please ?
I have the Multiplexed MultiECUScan to aid in any further diagnoses .


Fattrucker

 

[TerryL]

Throttle body, if it's a Fiat. Water from an incorrectly fitted, or absent, gutter tray drips onto it - you might see rusty tracks down the underbonnet earth point - and causes corrosion in the wiring/throttle body. Mines a Multijet 150 but may well be the same. My "localish" Fiat Professional garage went straight to it after I'd run the gamut of throwing parts at it.
Incidentally, with those codes the engine warning light should be on; think you may be right about a missing or even blown bulb!

 

[Fattrucker]

Throttle body, if it's a Fiat. Water from an incorrectly fitted, or absent, gutter tray drips onto it - you might see rusty tracks down the underbonnet earth point - and causes corrosion in the wiring/throttle body. Mines a Multijet 150 but may well be the same. My "localish" Fiat Professional garage went straight to it after I'd run the gamut of throwing parts at it.
Incidentally, with those codes the engine warning light should be on; think you may be right about a missing or even blown bulb!

Thanks I'll check any earth points I can see . Might be the root cause of a few issues .
Out of curiosity you don't happen to know what voltage I should be seeing at the MAF sensor connector do you please ?
I'm getting 4.98v - 4.99v . I thought it whould be 12v or thereabouts , but 5v wouldn't be unusual for some sensors .
But 5v when it should be 12v would correspond to the "No Signal" message I'm getting .

Fattrucker

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[Fattrucker]

Thanks I'll check any earth points I can see . Might be the root cause of a few issues .
Out of curiosity you don't happen to know what voltage I should be seeing at the MAF sensor connector do you please ?
I'm getting 4.98v - 4.99v . I thought it whould be 12v or thereabouts , but 5v wouldn't be unusual for some sensors .
But 5v when it should be 12v would correspond to the "No Signal" message I'm getting .

Fattrucker

Sorry I forgot to add that I fitted a genuine Marelli throttle body just over twelve months ago due to sticking .
This was one of the things I've looked at already . Everything looked fine .
Internally the circuit board was clean and devoid of corrosion .
The blade is also clean , shiny , moves freely and makes the "snap" / "click" noise quite clearly .

Fattrucker

 

[Landy Andy]

Could your EGR valve be stuck open?