C5X7 spawn of Satan !

[sparksie]

Hi all
My nightmare with the visiting C5 took a new twist today.
For several weeks now, it has been started, moved into/out of a shed and turned off again, never getting a chance to warm up.
I explained to my neighbour that that's particularly bad practice with modern diesels, so today, anticipating I'd be calling to finally have a proper go at the wipers, he transferred his insurance and went for a longer run. Sadly, the car had other ideas and less than 3 miles from home it put on the EML and went into limp home mode.
I was busy when the call came, so he nursed it home and I went to have a look as soon as I could.
This is a 2008, X7 1.6HDI VIN VF7**************[VIN obfuscated, can be read by forum staff]
I fired up my Lexia and found the integral ecu cooling fan open circuit or too hot.
I took a pic of the code on my phone, but in my frustration, seem to have deleted it, so I'll have to go back and do it again, unless someone knows this fault.
Presumably this means the ECU has to come out, for the fan to be replaced, but just in case it's something simple, where should I be looking?
I don't even know where the ECU lives on this car and I didn't try to find it because it was teeming rain and I may have been less gentle than is appropriate, had I found it.

[picassodad]

Parts diagrams will show you where the ecu lives, somehwere needing a fan for cooling so probably inside the nice dry car.

[GiveMeABreak]

We will need the code Sparksie - as it could be referring to any one of 30+ ECUs on this car.

[sparksie]

Yup, thought so.
I'll arrange to go down there later on and plug in again.
Wish I could tactfully wash my hands of it.
This car would be donating parts to keep others going, had I not helped out and, as time goes on, I'm thinking that might well have been the best option.
I think maybe I'm relearning why secondhand values of anything bearing a chevron badge fall off such a cliff.
What potential owner of a 10 year old car could possibly afford to pay for the amount of professional time this one is taking up? And then there will be parts cost, if I ever get as far as fixing it. That alone might be enough to write this one off, even with me giving my time for free.

[GiveMeABreak]

The codes are really important and preferably before any bypassing / splicing / etc. of wiring because it could affect the fault reporting. Many of the relays on these are the integrated type on the BSI so that adds a level of complexity to troubleshooting to start with.

[sparksie]

P0483 is the one I'm concerned about
There's also a P2408 that wasn't there yesterday and two others that may be relevant.
P1351, which is to do with the glow plugs and P0193, which is to do with fuel pressure.
Not sure what the state of play is with the additive, but as that's only just appeared, I think it can be discounted for now.
The glow plugs are not needed, so not going to worry about them for now, either.
So, there may be a fuel pressure issue, which certainly could cause performance issues and even a failure to proceed, if bad enough, but is not likely to do major damage.
Lack of cooling to an ECU will in all probability kill it, so that's the top priority, IMHO

[GiveMeABreak]

P0483

Description of the fault code: Cooling Function Incorporated in the ECU ( electric cooling fan unit): Open circuit.
Description of the diagnostics: The line is in open circuit for more than 5 seconds.
Conditions of activation of the diagnostics: Consult the associated contexts for the Pcode forwarding conditions.
Conditions of disappearance of the fault: Ignition on.
Down-grade modes if fault present: Diminution of the coolant temperature thresholds to cut the aircon compressor.
Switching on of the warning lamp and/or warning message: N/A
Main customer complaints likely:

• The cooling fan to operate permanently at maximum speed.
• Battery discharged

Suspect areas:

• Electric cooling fan unit
• Electrical harness
• Connector

P1351
Pre-heating relay circuit: Coherence; Relay supplied and glow plugs not supplied - common error and won't go into detail on that.

P0193
After sales description of the fault code Fuel pressure signal: Open circuit or short circuit to the plus
Description of the diagnostics: The fault appears if the voltage of the fuel pressure signal is greater than the maximum threshold of 4,8 V for 40 milliseconds or 2 engine revs.
Conditions of activation of the diagnostics: Consult the associated contexts for the Pcode forwarding conditions.
Conditions of disappearance of the fault: Ignition on.
Down-grade modes if fault present:

• Engine stopped.
• Deactivation of the reporting of faults associated with the high-pressure fuel injection common rail pressure
• Limitation of pressure in the fuel high pressure common injection rail

Switching on of the warning lamp and/or warning message: Warning lamp MIL.
Main customer complaints likely:

• Hesitation / Timing
• Unwanted acceleration
• Noise
• Smoke from the exhaust
• Lack of power
• Starting problem

Suspect areas:

• Electrical harness
• Connectors
• Fuel high pressure sensor
• Engine ECU

[GiveMeABreak]

Given all you have said, I am beginning to suspect the BSI is at fault as all of these lighting issues feed back to it. Even the rear lamp unit supplies for the fog lamps specifically have separate left and right feeds for each fog lamp back to the BSI. The fogs should not operate without the lighting of the main headlamps. The common denominator in all your lighting issues would point back to a problematic BSI.

[GiveMeABreak]

Having said that, there is also one other common issue - and that is Maxi Fuse 1 in the engine compartment Fuse Box. MF1 is responsible for the Fan (50A), plus the additional heater burner (where fitted), air conditioning and fog lamps.

Maxi Fuses 4 & 8 are also concerned with BSI supply.

Maybe it is worth a look at the maxi fuses for oxidation / condition.....

[EDC5]

I'm surprised tha the ECU is cooled by a fan. I thought they were all passively cooled?

[wheeler]

I'm surprised tha the ECU is cooled by a fan. I thought they were all passively cooled?

The cooling function incorporated into the ECU is talking about the injection ECU control of the radiator fan. Ive never seen a Citroen yet with a seperate fan to cool the injection ECU (i have seen it on some Mercedes models). I have never taken the ECU out an X7 yet so can say for sure but the mk 1 C5 100% doesn’t have an ecu fan & this fault can appear on them.

[bobins]

Am I correct in thinking that (at least on some variants) the radio / satnav / entertainment gubbins in these has its own cooling fan ? I'm not aware of any other active cooling for electronics on the X7.

[GiveMeABreak]

Wheeler is right - it's not talking about an ECU=cooling fan , but the Injection ECU control of the Engine Cooling Fan. You can see the Fan (1513) to Engine ECU (1320). The other 2 wires are the Fan High Speed and Fan Module Power Supply wires to the Engine Fuse Box.

@ Robin: Yes they do, but in most cases they are woefully inadequate leading to overheating issues - luckily my double DIN NG4 has plenty of space and ventilation inside to assist this, but overheating has been the cause of a lot of unit failures.

[sparksie]

Oh, ok.
That sounds like maybe it's the right track.
Interesting that you say the fog lights should only work when the headlights are on.
That is exactly what happens... theres just no way to turn them off, except to turn on the sidelights, or turn off the ignition.
Day or night, any switch position, other than sidelights, turning on ignition brings the headlights on. Headlights being on enables the foglights.
So, if I'm understanding correctly, the problem lies in the headlight controller, which is not turning them off unless the sidelights are on.
In any case, I've decided to ignore that and train the owner to always switch the lights on manually, even thought they're already on.
But, I have to solve the running issue, which has developed during the weeks it's been sitting idle over here.
There's reason to hope corroded fuses could have developed under the conditions that have prevailed here, over that time.
Another visit, with a can of contact cleaner, seems like a worthwhile investment

[sparksie]

In view of the recent history, with the front end plastics all having been replaced, I suppose there's more than a passing chance the radiator fan could have been accidentally unplugged, though in the distance travelled, that's unlikely to bring on the mil, or initiate limp home mode.
Hopefully tomorrow will be dry and bright, so I can have a proper look.