Technical Ducato Motorhome 2.0 HDI, 2003, Fuse 11 blowing

[Izzys Owner]

Hi All,
Fuse 11 in the engine compartment takes about 4 seconds to blow when the ignition is switched on. It says it's one of the fuses for the engine control unit but the only effect is to stop the speedo and odometer working. The red engine warning light comes on but everything runs ok apart from the speedo. This happened in the wilds of northern Scotland and I've done about 700 miles since to get home with no other problem (currently using satnav for speedo).
I temporarily replaced the fuse with a piece of 5A wire to see how it blows and you could see it slowly warm up before it blew, so not a short circuit. Anyone heard of this fault before?

 

[Izzys Owner]

Hi All,
Fuse 11 in the engine compartment takes about 4 seconds to blow when the ignition is switched on. It says it's one of the fuses for the engine control unit but the only effect is to stop the speedo and odometer working. The red engine warning light comes on but everything runs ok apart from the speedo. This happened in the wilds of northern Scotland and I've done about 700 miles since to get home with no other problem (currently using satnav for speedo).
I temporarily replaced the fuse with a piece of 5A wire to see how it blows and you could see it slowly warm up before it blew, so not a short circuit. Anyone heard of this fault before?

Apologies, this is a fiat engine but it's badged as a Peugeot Boxer chassis, don't know if that makes a difference.

 

[Crossingkeeper]

I recollect this fault being mentioned on the forum before and thought I'd saved the link but frustratingly can't now find it and can't come up with the correct search terms to retrieve it.

From memory fuse 11 also supplies an electrical heating element in a pipe which is only really needed in cold climates and the fix is to disconnect this element.

This isn't much help unless you can identify this pipe but may reassure that it could be a simple fix.....

EDIT.... found a relevant thread:

Technical - fiat ducato 2.8jtd motorhome fault codes

hi have had two faults which main fiat dealers and other so called auto electricians cant solve.First engine starts ok but engine light stays on followed by the heater coil light flashes on and off for about thirty seconds then goes off. Engine still runs fine but my speedo does not work either...

www.fiatforum.com

 

[Communicator]

Hi Izzys Owner,

I am almost certain that you have a faulty oil vapour heater. Unfortunately my information is biased towards my own 2.8 JTD, so I cannot immediately find diagrams for yours. The principles are however the same, so it should not be impossible to locate the faulty component.

The general system is follows. Blow by gases are vented from the crankcase to an oil vapour separator. The separated engine oil is drained back to the sump. Remaining gases which include water vapour a connected to the outlet of the air filter via a non return valve.

Locate the air filter outlet pipe. There will be a smaller pipe teed into it via a non return valve. Follow this pipe back towards the engine. The oil vapour heater will be tapped into the pipe, probably with the connecter on the lower side. Unplug connector and replace F11. You should be OK to run like this, except in extreme winter conditions.
Here is a link to what I think will be an appropriate eLearn wiring diagram for your emgine. The oil vapour heater "O007" is at the bottom RH corner of the drawing. Note the number of devices connected to the same supply almost immediately above. However some of these could be alternatives.

I am also attaching an Iveco explanation of the oil vapour separator. This is for a 2.8 JTD, shows the basic principle, but does not include the heater. (Used to vent to atmosphere.)

 

[Izzys Owner]

Hi Izzys Owner,

I am almost certain that you have a faulty oil vapour heater. Unfortunately my information is biased towards my own 2.8 JTD, so I cannot immediately find diagrams for yours. The principles are however the same, so it should not be impossible to locate the faulty component.

The general system is follows. Blow by gases are vented from the crankcase to an oil vapour separator. The separated engine oil is drained back to the sump. Remaining gases which include water vapour a connected to the outlet of the air filter via a non return valve.

Locate the air filter outlet pipe. There will be a smaller pipe teed into it via a non return valve. Follow this pipe back towards the engine. The oil vapour heater will be tapped into the pipe, probably with the connecter on the lower side. Unplug connector and replace F11. You should be OK to run like this, except in extreme winter conditions.
Here is a link to what I think will be an appropriate eLearn wiring diagram for your emgine. The oil vapour heater "O007" is at the bottom RH corner of the drawing. Note the number of devices connected to the same supply almost immediately above. However some of these could be alternatives.

I am also attaching an Iveco explanation of the oil vapour separator. This is for a 2.8 JTD, shows the basic principle, but does not include the heater. (Used to vent to atmosphere.)

Hi all, thanks for the heater info. Unfortunately, that has not cued my fuse 11 problem. Looks like I'll have to start taking the wiring loom apart and teaching each cable

 

[Izzys Owner]

Hi all, thanks for the heater info. Unfortunately, that has not cued my fuse 11 problem. Looks like I'll have to start taking the wiring loom apart and teaching each cable

Oops, should be "testing" each cable (but I can confirm the 2.0Hdi has an oil vapour heater that I didn't know was there).

 

[Izzys Owner]

Oops, should be "testing" each cable (but I can confirm the 2.0Hdi has an oil vapour heater that I didn't know was there).

I've now traced the wiring and a single orange/black goes to pin 4 of the large plug on the ecu, bolted to the nearside inner wing. It seems unlikely the ecu would have a fault that shows up like a short circuit and still keep functioning. Anyone know where I can find the ecu pin designations (photo of ecu label attached)?

 

[Anthony489]

Hi

On your vehicle, Fuse 11 in the engine compartment fuse box supplies eight different fairly low-powered components which have been designated "Electronic Injection Secondary Services". From this I assume that they needed for best operation but perhaps not absolutely vital. If Fuse 11 were to blow while driving, you would not therefore lose all power.

If you look at the schematic linked by Communicator, you will see that the following electrical devices are all driven by Fuse 11:

O 007 Oil Vapour Heater
K 031 Water in Diesel sensor
K 041 Air Flow Meter
L 030 EGR solenoid valve
L 005 Injection pump control solenoid
M 015 Glow plug controller (Logic Circuits Only)
K 084 Speedometer sensor
L 062 Throttle body solenoid valve

There may be some detail variations for the 2.0 engine compared with the larger capacity ones, but you get the general idea.

Maybe not a very clever idea of Fiat to hang quite so many things off one Fuse, but that's how they are made, even the later X250 models.

Note that the ECU is NOT one of these components, it has its own fused supplies. I think your Orange/Black ECU wire is a blind alley.

The wire colours are mostly AN which is Light blue/Black. with one wire A which is light blue. There may well be wire junctions hidden in the loom.

The excess current which is blowing the fuse is either due to one of the above components being faulty, or the wiring between them having a short to ground. The "slow" fuse blowing makes me think a component failure is more likely, a wiring short would cause a rapid blow.

I suggest you disconnnect the items one by one. If the Fuse holds, you then know which component is faulty. Alternatively, if the Fuse still blows with all of them disconnected, look for a short on the Light Blue/Black wires.

 

[Communicator]

You can get the required info by using eLearn, which I linked to in post #4 of this thread.

By designations, I am assuming that you mean allocations, rather than pin numbering.

A brief inspection of the pin numbering obtained by scrolling down below the diagram E5050 linked to in post #4 will reveal that it is flawed. I am attaching my own corrected version, which is probably correct for your ECU as well as my 2.8JTD.

An alternative approach to pin allocations may also be obtained from eLearn, by following the route descriptions, engine, fuel system. Unfortunately on the 4cardata site the text is cropped and much interesting info is not available. I recommend getting your own CD or virtual download.

I think that it was @Ocwobio, who stated using eLearn was "like peeling the layers off an onion". I have quoted this several times.

 

[Communicator]

================================================================================================

There may be some detail variations for the 2.0 engine compared with the larger capacity ones, but you get the general idea.

Maybe not a very clever idea of Fiat to hang quite so many things off one Fuse, but that's how they are made, even the later X250 models.

Note that the ECU is NOT one of these components, it has its own fused supplies. I think your Orange/Black ECU wire is a blind alley.

The wire colours are mostly AN which is Light blue/Black. with one wire A which is light blue. There may well be wire junctions hidden in the loom.

The excess current which is blowing the fuse is either due to one of the above components being faulty, or the wiring between them having a short to ground. The "slow" fuse blowing makes me think a component failure is more likely, a wiring short would cause a rapid blow.

I suggest you disconnnect the items one by one. If the Fuse holds, you then know which component is faulty. Alternatively, if the Fuse still blows with all of them disconnected, look for a short on the Light Blue/Black wires.

May I register my agreement with the above. An alternative approach may be to disconnect as many items as possible, then re-energise. Best to keep a tick sheet in case you forget something.

 

[Izzys Owner]

Hi

On your vehicle, Fuse 11 in the engine compartment fuse box supplies eight different fairly low-powered components which have been designated "Electronic Injection Secondary Services". From this I assume that they needed for best operation but perhaps not absolutely vital. If Fuse 11 were to blow while driving, you would not therefore lose all power.

If you look at the schematic linked by Communicator, you will see that the following electrical devices are all driven by Fuse 11:

O 007 Oil Vapour Heater
K 031 Water in Diesel sensor
K 041 Air Flow Meter
L 030 EGR solenoid valve
L 005 Injection pump control solenoid
M 015 Glow plug controller (Logic Circuits Only)
K 084 Speedometer sensor
L 062 Throttle body solenoid valve

There may be some detail variations for the 2.0 engine compared with the larger capacity ones, but you get the general idea.

Maybe not a very clever idea of Fiat to hang quite so many things off one Fuse, but that's how they are made, even the later X250 models.

Note that the ECU is NOT one of these components, it has its own fused supplies. I think your Orange/Black ECU wire is a blind alley.

The wire colours are mostly AN which is Light blue/Black. with one wire A which is light blue. There may well be wire junctions hidden in the loom.

The excess current which is blowing the fuse is either due to one of the above components being faulty, or the wiring between them having a short to ground. The "slow" fuse blowing makes me think a component failure is more likely, a wiring short would cause a rapid blow.

I suggest you disconnnect the items one by one. If the Fuse holds, you then know which component is faulty. Alternatively, if the Fuse still blows with all of them disconnected, look for a short on the Light Blue/Black wires.

Hi Anthony,
That's really thorough, thanks. I'll track my orange/black more carefully but will definitely start unplugging the components from your list.
Cheers.

 

[Izzys Owner]

Hi Anthony,
That's really thorough, thanks. I'll track my orange/black more carefully but will definitely start unplugging the components from your list.
Cheers.

OK, so I'm a slow learner! I was looking at the wrong heater, it WAS the oil vapour heater. Now disconnected and all good. Many thanks to all of you for your help and for giving me the confidence to track the problem down. Of course, that just leaves the one question of what actually is the function of the heater? Does it protect the turbo from cool vapour, perhaps?
Thanks again.

 

[Communicator]

Engine combustion products contain water vapour. The heater is to prevent this vapour freezing. As has previously been suggested on a linked thread, this is probably only happens in extreme climatic conditions, e.g. winter in Northern Scotland or Scandanavia.

 

[Izzys Owner]

That makes sense. Thanks.

 

[Izzys Owner]

That makes sense. Thanks.

Last words on this: I contacted my local fiat dealer and the parts guy went hunting through his system. The part is called an oil blow-by heater (part no. 1343666080) and is the complete hose set with heater. He found it by looking for country variants and it is listed as being for Northern Europe (eg Scandinavia) it is not sold by fiat in the UK all of which shows that Forum members are right in saying it's for cold countries and that its not worth replacing in the UK. If anyone wants one, though, I can get one for €183!