Hi all i'm trying to save my beloved scudo 1.9d 2004 converted campervan. mileage is 140k.

About a month ago the engine chick ( MIL ) light came on, I tried to scan it with an OBD2 reader but there were no codes and erasing the non existent codes did not remove the engine light. The van was running perfectly so i ignored it. Just went for the MOT and they have changed the check points and now an engine light on is a automatic major fail. Taken it to 2 garages for diagnostics and both come back with the same thing that there are no error codes so nothing they can do.

I have had the van for 8 years and its been fantastically reliable and it breaks my heart to have to scrap it because of a little light bulb when still running great.

I'm reasonably competent with repairing cars and have good non-car electrical experience but i'm stumped as to how to proceed. Has any one else had this problem? Any advise on how to diagnose the issue? Could it be a short in wiring, faulty ECU, a sensor issues that instantly triggers the check engine light but does not give a code? I would be eternally grateful for any thoughts!

Some other information that might be useful. When the key is turned one click (dash light illuminated but car not started) the OBD reader indicates the MIL light is on (which it is) after starting the car the OBD reader says the MIL light is off (though it stays on).

I also have a small air leak in the fuel lines which i have not yet been able to remedy.

Thanks in advance

Kieran

Hi. Worth trying a place with specialist fiat-alfa kit.

My generic OBD reader doesn't read the fuel temp error that my Multiecuscan tells me all about.

Charlie

Yeah i'm not sure what code reading kit the two garages I went to were using. They said they had professional level diagnostics equipment but i don't know if it was Fiat specific. Do you think that could make the difference? What's really weird is that when i start the engine up the obd2 reader says the MIL is off (when it is actually still on). Wondering if my ECU is faulty. Pulled off the dash and inspected the PCB and there is no obvious damage or shorts so a voltage to turn the MIL light on must be coming from the ECU but why ECU is giving the signal but telling my there is nothing wrong and even that there is no MIL light signal being given is very weird.

cheers

Where is the vehicle based?

The ecu can be driven to put the mil on and off again as a test..

Its possible this is happening..
Therefore no specific code -fault to see. But if you are close enough to get these tests performed with a copy of multiecuscan.. that would be a cheap and easy start.

Even the FREE version would (should) do these basic tests.

Charlie

kmonk said:

Yeah i'm not sure what code reading kit the two garages I went to were using. They said they had professional level diagnostics equipment but i don't know if it was Fiat specific. Do you think that could make the difference? What's really weird is that when i start the engine up the obd2 reader says the MIL is off (when it is actually still on). Wondering if my ECU is faulty. Pulled off the dash and inspected the PCB and there is no obvious damage or shorts so a voltage to turn the MIL light on must be coming from the ECU but why ECU is giving the signal but telling my there is nothing wrong and even that there is no MIL light signal being given is very weird.

cheers

Click to expand...

Hi,
Fiat specfic software like Multiecuscan will actually allow you to turn the light on and off from the computer as well as giving better code reading capability. If you have a Windows laptop (even an old one running XP) MES costs 50 euros www.multecuscan.net and an interface and leads about £25

HOWEVER, MES does not list a 1.9 D Scudo. What engine is fitted (HP no of valves, ECU type, engine code)?
It is possible that the output of the ECU that drives the MIL has a fault. If the driver is shorted the microprocessor will tell it to turn off but it will stay on. Less likely is a short circuit in the wiring. Disconnecting the wire at th ECU will help diagnostics.
If you are near Cambridge I'd be happy to have a look.
It has been known for a faulty MIL to be disconnected from the ECU and connected to another light than comes on and goes oss like ABS, airbag or even oil pressure. This makes it look like it's working.
EDIT,
Just checked and it looks like it has a PSA engine so Citroen /Peugeot software may be more useful, if availble.


Robert G8RPI.

Firstly thanks so much for the advise. I've never had electrical issues with my van before so this is all a bit new to me but i'm reading lots and learning quickly and these comments are invaluable in steering me in the right direction.

I'm in Plymouth and if there is anyone local that thinks they could help I would gladly compensate you for your time with money, a case of homebrew or a steak dinner.

Charlie - I understand a bit better now, i have an ELM327 OBD2 reader which appears to be compatible with Multiecuscan but as Robert points out its not listed as being compatible with my vehicle. I will give it a try anyway and thanks for the tip.

Robert - Sadly i'm not near Cambridge and the old MOT expires on Monday so I won't be able to get up there (or even to another garage so i'm on my own now). Can you suggest another vehicle make/model specific software that would be more suitable for my ECU than Multiecuscan? The ECU code is PSA:9650359580 (is that what you were asking for?). My initial thought is the same as you suggest that there MIL circuit is stuck closed. I had also come to the conclusion that one way around it would be to parallel the MIL with the oil warning light which goes out when the van is started. Spent all day probing the dashboard PCB and multi wire connection plugs that come off the back trying to find neat wiring solution to this effect... just for curiosity you understand, obviously I would never tamper with such a system. Also pretty scared of messing it up and shorting everything out.

thanks again guys

Hi,
Clearly a PSA engine and ECU so MES won't work. I'm pretty sure you have a faulty ECU. Looks like about £150 for a replacement . It also appears to need recoding. www.cartechelectronics.com/plug-play-engine-ecu-psa-9650359580-r04080036c-9655574380-dcn2-dwlc12/


Robert G8RPI.

Robert - thanks for this further information probably saved me a few hours of ripping out what little hair i have left trying to get Multiecuscan to work. £150 for a new ecu is not ideal but honestly i was expecting worse. Now to decide whether or not to take a punt on it, horrible feeling to potentially be throwing good money after bad and finding out the ecu was not the issue. I haven't given you much information but from the symptoms i have described would you rule out (in a most probable sense) the possibility of a faulty sensor somewhere that is causing the MIL to come one instantly after erasing (the non existent) codes?

cheers

Kieran

Hi. There are a FEW owners on here with the ULYSEE people carrier.. its also a joint venture Fiat And PSA.

Being an oddball the owners tend to have their own Nexia? Sortware kit.

Worth posing a question there.


Generally nowadays ECU swaps are simpler with a lockset.etc..


But again pug.citroen experience will save you grief and expense.

All the best. Charlie

Sorry one more question guys

I've seen a kit on ebay consiting of an ecu, ignition barrel and relay block (hopefully i'll be able to give the url in next post when my post total gets to 5)

Do you know if i could do a straight swap with this kit without recoding? I don't fully understand what the recoding does, is it just for the immobiliser (hence why this kit comes with a new ignition barrel) or is there more to it than that?

thanks

here is the url to the kit

https://www.ebay.co.uk/itm/EXPERT-S...062191?hash=item441621602f:g:a6gAAOSwM~tab0~Q

cheers

Hi,
I guess it depends how much value you put on your time to fit the extra parts and the hassle of having too use two keys (the kit shown does not include door locks). As the diagnostics you have shows that the ECU "thinks" it is turning the MIL off and is not showing any fault codes there are realy only two possible faults, The ECU output has failed to permanent "ON" or ther is a short circuit elsewhere in the wiring. I asssume the light is high for on and given the age of the car it is a direct drive, not via a data bus. As shorts to positive are rare it's likelt to be ECU.

The only other thing you can try is if you have a circuit diagram or pin-out for the ECU, cut the wire for the MIL near the ECU (or pull the pin if you have the tool). If the light goes out it is 99% likely to be the ECU. If it stays on start looking for a short circuit, but double check you have the right wire / pin. If the light stays on with ECU unplugged it's likely to be a short outside the ECU, but only about 60% confidence as many other circuits are affected.
There is a service manual in the downloads section

https://www.fiatforum.com/downloads.php?do=download&downloadid=312
but I've not downloaded it myself.

HTH,
Robert G8RPI.

Hi,
I've looked at th diagrams and there is not an obvious "MIL" light on the ones I have.

Exactly what is the symbol on the light and can you confirm


1/ Year of car
2/ Does car have ABS
3/ Is the engine turbocharged
4. Is the engine common rail.


Robert G8RPI.

Thanks again Robert

I don't value my time very highly, ha ha. Basically I have never once paid for repairs on my van (other than tyre fitting and mot) and up till now i have fixed everything myself (this is my first vehicle I have owned). I would much rather spend my time learning a new skill/trick than pay someone and learn nothing.

When i bought the van it had a differnt ignition key to the door locks so its possible that the ECU has been changed before. So no additional issue with extra keys and i feel like i could change the ecu, barrel and immobiliser and would be happy to try and add another string to my bow. At £70 it will be less disappointing if it doesn't work especially if it is no differnt to sending the ECU for a recoded one (other than the labour).

Everything you have said makes total sense and is more or less the conclusion i had come to but it's great confidence builder to have someone with experience come to the same conclusion. I've already pulled the pin for the MIL lamp out of the cable harness that goes into the dash PCB but stopped short of switching the ignition on to test as its dark now and i'm totally spent so don't want to do something stupid. I'll give it a whirl tomorrow and if I can rule out a wire short then i think i'll take the plunge with a used ECU swap.

thanks again so much to you and Charlie, you've been very generous with your time.

Hi Robert

To answer your questions,

the symbol is the outline of an engine with 3 arrows pointing out in differnt directions but originating from the same point. The light is yellow/orange.

1. the year is 2004
2. it doesn't have ABS
3. It doesn't have a turbo
4. I'm not 100% if its a common rail as i'm not fully sure what that is. It has a high pressure pump and from memory it has individual pipes from the high pressure pump to each injector.

That reminds me of another bit of information that might be worth nothing. Last year the engine would turn over but not start. In the end i found the solenoid between high pressure fuel pump and the injectors was not opening. I replaced this three wire solenoid with a single wire replacement. I had assumed the solenoid coil had burned but is it possible that the ECU was not sending the signal to open? (possible further evidence that the ECU is on the way out?)

thanks

Robert - Looking at the work shop manual it so far i have not seen anything that matches my vehicle as they all seem to be slightly older with differnt dash layout. The closest is on page 4 of the 2002 updated instrument panel but mine has a clock instead of a rpm counter and the engine light is in a differnt location (other than that they appear the same). But i do see what you mean about no MIL as on a previous version it suggests what i call the MIL light they call an

Hi,
I found the correct schematics (I think) and it seems the MIL is ground switched.




This being the case a short in the wiring is more possible. If you have a multimeter put it on ohms and connect btween a good chassis earth and the wire you have pulled from the cluster with the ignition off. I presume you will get a low reading, less than 500 ohms (If you don't see low resistance at this stage try the diode check function on your meter if it has one). If you do, unplug the ECU and check again. If you still get a low resistance the fault is in the wiring. If it goes high resistance (>1000 ohms) The fault is in the ECU. This assumes the light went out when you pulled the pin from the cluster.

If test indicates ECU fault it looks like using a kit from ebay would be the cheapest repair.


Roert G8RPI.

Hi Robert, thanks again for your continued support.

I did the test you suggested (if i understood it correctly) which was to leave the wiring harness attached to the PCB of the instrument cluster. I then stuck a pin (in order to get a contact with the DMM) into terminal 14 which has the wiring code 480 (as indicated by electrical schematic, i'd also found this earlier by probing the PCB). I then attached the black DMM probe to the pin on the wiring harness and the red DMM probe to battery negative. Like this i got a reading of 650ohms (with the probes reversed i got a very high resistance). I then removed the ECU and repeated the test and this time i got a resistance of 750ohms. Do these values reveal anything? My DMM is very cheap and i don't trust it that much and I will repeat the test tomorrow after i borrow a good DMM from work. I tried the same tests in diode function but it gave the same values.

I also removed pin 14 wire 480 from the wiring harness and after reconnecting the ECU I switched the ignition on and the MIL did not light up so it looks like the correct wire. I also found the fuse for the MIL light which is number F6 in the engine bay. Reconnecting the wire to the harness and then removing the fuse also caused the MIL not to light up with the ignition.

Any thoughts?

thanks

Hi Robert

I realised I probably didn't understand your instructions before because I tested the resistance (with and without ECU connected) with the wiring still connected to the cluster and therefor might not have isolated the wire in question. I think what you were asking me to do is removed the wire associated with the MIL light from the cluster and test the resistance with and without the ECU in order to directly test for a short to ground in the wire that links the ecu to the cluster MIL. I did the test again and found 650ohms with the ECU connected and very high resistance with the ECU disconnected. Does this further point to a faulty ECU?

Does the fact that there is a resistance of of 650ohms without the ECU being powered indicate that the MIL light circuit is stuck closed, or is the ECU likely to have this switch as Normally closed in a non powered state?

thanks

Kieran

kmonk said:

Hi Robert

I realised I probably didn't understand your instructions before because I tested the resistance (with and without ECU connected) with the wiring still connected to the cluster and therefor might not have isolated the wire in question. I think what you were asking me to do is removed the wire associated with the MIL light from the cluster and test the resistance with and without the ECU in order to directly test for a short to ground in the wire that links the ecu to the cluster MIL. I did the test again and found 650ohms with the ECU connected and very high resistance with the ECU disconnected. Does this further point to a faulty ECU?

Does the fact that there is a resistance of of 650ohms without the ECU being powered indicate that the MIL light circuit is stuck closed, or is the ECU likely to have this switch as Normally closed in a non powered state?

thanks

Kieran

Click to expand...

Hi,
Sorry for not replying earlier, been doing some DIY around the house.

Yes I did in thend for the test to be with Cluster disconnected to take the lamp out of crcuit. I forgot to say that the black lead of the meter goes to earth for the test. If you had the meter this way around for the second test then it looks like a faulty ECU. You certainly don't have a short circuit in the loom. If you had Red meter lead to ground the 650 reading could be due to a diode in the ECU. Summary of test wire to chassis results and fault probability



Cluster and ECU disconnected <100 ohms 100% Short in wiring, >1000 ohms 90% fault in ECU.

Just ECU connected <100 ohms 100% faulty ECU, >100 ohms but less than 1000 ohms 90% faulty ECU. >1000 ohms is inconclusive.


In summary I think it is 90% certain your ECU is faulty.


Robert G8RPI.