NP300 D23 YD25DDTI Going Into Limp Mode

[thathawkeye06]

Hi, Josh here i got a 2020 NP300 D23 with the YD25DDTI engine and i’m pretty confused on what is happening with my truck right now. It’s going into limp mode but i cannot determine why, the problem is it does not want to rev past 2,500 RPM’s and can get up to 3,000 RPM’s but i gotta force it like going downhill on first gear for example, mine is a 6 Speed Manual btw, i’ve cleaned the MAF, changed the MAP for a brand new oem one, changed the intercooler piping and cleaned the intercooler, lubricated the vgt actuator, cleaned the SCV, no boost leaks, the only thing i noticed that i think is not normal was that my fuel pressure got up to 192 MPA at WOT but other than that nothing, in my country the YD25DDTI comes with no EGR so the problem is not that, and i did a DPF delete.

I’ve tried resetting the ecu but this only fixes the trouble for a short time and then goes back to not revving past 2,500 RPM’s but last week i did this and the problem got away for a whole week but the truck is back on limp mode, the only code i got is a P0380 for the glow plugs but my truck starts right up and no rough idle and just a tiny small bit of white smoke when i turn it on in the morning and i guess that’s because of the DPF delete, anyone got any insights on a similar trouble going on.

Note to mention that the fuel rail pressure only goes up to a maximum of 90 MPA at WOT when it’s on limp mode. When it’s functioning as it should i got a maximum of 192 MPA.

 

[Old.Tony]

It could be the SCV, which produces a "limp mode" without codes or Check Engine Light. The SCV will either be dirty or damaged.

First step: put some GOOD injector cleaner in the tank. Liqui Moly Fuel System Treatment is my general go-to but you can use others, maybe Google up some reviews on ones you have locally.

If you can't get no satisfaction (apart from the record being upside down* ) you're probably going to have to replace the SCV.

In Australia, we can buy a new SCV from Nissan for around $240 or we can pick up a cheapy on eBay for around $40. The cheapies are ok probably 75% of the time. I don't know what your local Nissan dealer will try to steal from you for a new SCV.

 

[thathawkeye06]

It could be the SCV, which produces a "limp mode" without codes or Check Engine Light. The SCV will either be dirty or damaged.

First step: put some GOOD injector cleaner in the tank. Liqui Moly Fuel System Treatment is my general go-to but you can use others, maybe Google up some reviews on ones you have locally.

If you can't get no satisfaction (apart from the record being upside down* ) you're probably going to have to replace the SCV.

In Australia, we can buy a new SCV from Nissan for around $240 or we can pick up a cheapy on eBay for around $40. The cheapies are ok probably 75% of the time. I don't know what your local Nissan dealer will try to steal from you for a new SCV.

Thanks for the reply, i’ve tried anything even cleaning the SCV and no luck, but tomorrow a friend of mine who sells nav parts will send me a good one tomorrow to test and see if the problem still keeps happening i’ll keep you informed on how it turns out.