Technical Ducato X290 error code P1581-15 (blow by problem)

[richarddgjames]

P1581-15 Blow by heater relay feedback; Short circuit to +battery or open circuit in 2017 Ducato X290 Multijet II 2.3 150BHP

Alerted to this by the engine warning light; Code P1581 (Short circuit to +battery or open circuit) in AlfaOBD and P1581-15 in mechanic’s report. Initially the warning light was constant but became intermittent. The internet says that this requires a new Blow by thingy and Fiat Professional concurred. When replaced it resolved the code and the warning light. The problem recurred 3 years later and I had it replaced by an independent garage for half the Fiat Pro price.

I could not find much on the internet about this; most of the info on the forum refers to the different setup in the X250 so this post is just to help anyone in a similar situation.

The part is officially called an Oil Return Temperature sensor. I understand that its job is to activate a solenoid in the pipe and it’s function is only relevant in very cold weather so safe to drive when warning light shows unless in Norway in winter.. I also understand that they fail fairly often although the mechanic thought I was unlucky for it to fail twice. They kept the part on the shelf. Part number P0005802052418. Costs around £150 (inc VAT). It is located in the rear of the middle of the top of the engine. The yellow fixing clip is a visual clue. It seems relatively easy to replace and if it happens again I will give it a go; needs jubilee clip removing from the main pipe (and mayby a new one if not reusable), the back pipe is undone using the yellow clip and pulled off and there is an electrical connection to the (engine’s) left to disconnect. Examining the replacement part gives a good idea of how the clip works. It is different to the descriptions I have seen of the pipe in the X250.

Fiat Pro charged £506 in 2022 and the independent garage charges £240 in 2025. About £150 if you DIY.

I hope this helps someone sometime.

 

[deejays]

P1581-15 Blow by heater relay feedback; Short circuit to +battery or open circuit in 2017 Ducato X290 Multijet II 2.3 150BHP

Alerted to this by the engine warning light; Code P1581 (Short circuit to +battery or open circuit) in AlfaOBD and P1581-15 in mechanic’s report. Initially the warning light was constant but became intermittent. The internet says that this requires a new Blow by thingy and Fiat Professional concurred. When replaced it resolved the code and the warning light. The problem recurred 3 years later and I had it replaced by an independent garage for half the Fiat Pro price.

I could not find much on the internet about this; most of the info on the forum refers to the different setup in the X250 so this post is just to help anyone in a similar situation.

The part is officially called an Oil Return Temperature sensor. I understand that its job is to activate a solenoid in the pipe and it’s function is only relevant in very cold weather so safe to drive when warning light shows unless in Norway in winter.. I also understand that they fail fairly often although the mechanic thought I was unlucky for it to fail twice. They kept the part on the shelf. Part number P0005802052418. Costs around £150 (inc VAT). It is located in the rear of the middle of the top of the engine. The yellow fixing clip is a visual clue. It seems relatively easy to replace and if it happens again I will give it a go; needs jubilee clip removing from the main pipe (and mayby a new one if not reusable), the back pipe is undone using the yellow clip and pulled off and there is an electrical connection to the (engine’s) left to disconnect. Examining the replacement part gives a good idea of how the clip works. It is different to the descriptions I have seen of the pipe in the X250.

Fiat Pro charged £506 in 2022 and the independent garage charges £240 in 2025. About £150 if you DIY.

I hope this helps someone sometime.

Great feedback and result - thankyou. I found this video which may be of assistance for anyone reading your excellent description:

 

[richarddgjames]

Great feedback and result - thankyou. I found this video which may be of assistance for anyone reading your excellent description:

Thanks deejays, that is excellent and didn't come up in my searches!

Perhaps I can put out a challenge;
As I understand that this part only becomes relevant in extremely cold conditions would it be possible to fool the computer into thinking it is working when it isn't?
1, Is the default (normal temperature) position for the valve powered or not powered?
2, If not powered, would the ECU expect a specific resistance (in the video; 16 ohms)?
3, If so, could a breakout cable with a 16ohm resister fool the ECU into thinking all is well without causing knock-on problems with other sensors?

If I have that all wrong then please forgive me for trying!

 

[MSjoberg]

Thanks deejays, that is excellent and didn't come up in my searches!

Perhaps I can put out a challenge;
As I understand that this part only becomes relevant in extremely cold conditions would it be possible to fool the computer into thinking it is working when it isn't?
1, Is the default (normal temperature) position for the valve powered or not powered?
2, If not powered, would the ECU expect a specific resistance (in the video; 16 ohms)?
3, If so, could a breakout cable with a 16ohm resister fool the ECU into thinking all is well without causing knock-on problems with other sensors?

If I have that all wrong then please forgive me for trying!

1. As I understand it, it's an electrical heater and not a valve
3. I think so

I don't know how the X250 or X290 might be different configured for different climate regions. But I do know the X244 was, it had blow-by heater as standard if sold new in Sweden, but not in Germany. This caused problems for some who had imported their used motorhome from Germany and drove it during winter in Sweden not knowing about this difference. I had one but never used in wintertime and it worked very well without this heater.