Technical Fiat Ducato voltage from acceleration pedal to ECU pin?

[Jorisv]

Hi Everyone, over 10 years I own a camper built on the 2002 Fiat Ducato, engine type 230 2.0 JTD.
Already travelled 130,000 km across Europe with great pleasure.

Will post my first question soon!

 

[Jorisv]

Hi Everyone, over 10 years I own a camper built on the 2002 Fiat Ducato, engine type 230 2.0 JTD.
Already travelled 130,000 km across Europe with great pleasure.
Driving from Estland back home (Netherlands) the Ducato occasionally went to limb mode with EML.
A lot of testing, measuring, forum reading already done and still ongoing.
Diagnosis: P0220 (acceleration pedal 2nd signal inconsistent).

Here one specific question: During normal conditions:
Voltage of 2nd signal varies between about 0.35 and 1.2 according to multimeter at pedal connector.
Voltage of 2nd signal varies between about 0.35 and 1.2 according to MultiEcuScan (MES) from OBD.

So far so good. But when the Ducato is in limb mode:
Voltage of 2nd signal varies between about 0.35 and 1.2 according to multimeter at pedal connector.
Voltage from MES is about 0.05.

Question: Is 0.05 volts also the actual voltage on the corresponding pin of the ECU?
Or can the actual voltage on that pin still be equal to the voltage on the pedal connector but
the ECU reports a different (lower) voltage due to the limb mode?

I was not (yet) able to measure the voltage at the ECU pin.
If anybody could clarify this, would be of great help!

 

[Communicator]

Hi Jorisev,

I am rather busier than usual this evening, so I will be brief.
Your vehicle is an x230 model. The x230, has an intermediate connector for the accelerator pedal connections behind the LHS dash panel. The connector is a known source of problems. Some members have chosen to remove the connector and solder the wires together. I have seen some photos in recent months, but I cannot find the thread at this time.

 

[Jorisv]

Thank you, Communicator, I will probe and replace this connector once I find it!

Another connector (occurring in several wiring diagrams and known as D004) seems to be absent in this x230.
I've looked beneath the engine's fuse holder, and everywhere but haven't located it.

My main question remains: can the voltage at an ECU pin be different from the one sent to OBD by design?

 

[Communicator]

Thank you, Communicator, I will probe and replace this connector once I find it!

Another connector (occurring in several wiring diagrams and known as D004) seems to be absent in this x230.
I've looked beneath the engine's fuse holder, and everywhere but haven't located it.

My main question remains: can the voltage at an ECU pin be different from the one sent to OBD by design?

I think that is most unlikely. It would not make any sense. If, as I suspect you have a faulty connector, then that could result in the ECU receiving a lower voltage.

Connector D004 is the engine connector on x244 models, on which the wiring is radically different to that on the x230.

 

[Jorisv]

I think that is most unlikely. It would not make any sense. If, as I suspect you have a faulty connector, then that could result in the ECU receiving a lower voltage.

Connector D004 is the engine connector on x244 models, on which the wiring is radically different to that on the x230.

This very helpful, so yes, now I understand it is very likely a problem of electrical connection!
Many thanks!

 

[Communicator]

@Jorisv

See this thread for photos of accelerator/ECU wiring connector.

 

[Jorisv]

@Jorisv

See this thread for photos of accelerator/ECU wiring connector.

That's a great tip. A came across these connectors but didn't relate them to D004, which is a massive connector.
Possibly, in the x230, the D004 connector is absent and implemented by several smaller ones.
I'll check it!

 

[Communicator]

That's a great tip. A came across these connectors but didn't relate them to D004, which is a massive connector.
Possibly, in the x230, the D004 connector is absent and implemented by several smaller ones.
I'll check it!

As I stated previously, the wiring for the x230 is different to that on the x244.. Most of the x230 wiring, for functions other than the engine is available, but I have not seen any wiring diagrams specifically for the x230, that apply to the engines.

 

[Jorisv]

@Jorisv

See this thread for photos of accelerator/ECU wiring connector.

Found! Behind the LHS dashboard indeed (see picture).
It is a 18-pins connector, for the 6 APS wires and other.
Perhaps it is the source of the faults; a good point for electrical checks.
Thank you!

 

[Communicator]

Found! Behind the LHS dashboard indeed (see picture).
It is a 18-pins connector, for the 6 APS wires and other.
Perhaps it is the source of the faults; a good point for electrical checks.
Thank you!

Are you sure that you are looking at the right connector? Other contributors mention a 6 way, and confirming by colour codes, and continuity testing.

 

[Jorisv]

Are you sure that you are looking at the right connector? Other contributors mention a 6 way, and confirming by colour codes, and continuity testing.

Good point! The right connector was hidden behind about several other ones, and it is a 6 way (see picture).
Before measuring anything I pulled out the plug a few mm, and made a short tour, and it made all the difference!
No faults reported, engine running fine.
Tomorrow I'll make a longer test drive...

 

[Communicator]

Good point! The right connector was hidden behind about several other ones, and it is a 6 way (see picture).
Before measuring anything I pulled out the plug a few mm, and made a short tour, and it made all the difference!
No faults reported, engine running fine.
Tomorrow I'll make a longer test drive...

I had thought of suggesting contact cleaner, for which I have become an advocate after using it to cure my key code problem. My son also used contact cleaner to fix an obscure PC memory card fault, even though they use gold plated connectors.

 

[Eternal Optimist]

I use contact cleaner on every connection each time I examine a connector. The hard bit is getting to them, so you may as well give 'em a blast while you're in there.

 

[Jorisv]

I had thought of suggesting contact cleaner, for which I have become an advocate after using it to cure my key code problem. My son also used contact cleaner to fix an obscure PC memory card fault, even though they use gold plated connectors.

I've applied contact cleaner. After 23 years the continuity of wire 6 (in this particular case) was hampered apparently.
Everything works fine (after 50km drive).
Many thanks to all of you for your great suggestions!