D40 Going into Limp Mode and throwing codes 1021 and 102B

[Hazlow]

My 2011 D40 YD25 diesel is throwing codes 1021 and 102b, and going into limp mode where it loses a lot of power.
Previously it would throw code 1021 every now and then, which I would clear and it would be fine for a while.

Now when I clear the codes, they come back in a few minutes.

Any ideas or experience with this?

From what I've found 102b is an exhaust temp code and 1021 might have something to do with the boost controller.

TIA

 

[Old.Tony]

1021 is a fault in the turbocharger boost control actuator, and
102b occurs when the exhaust pressure is the same as atmospheric pressure

1021 could be a faulty actuator, if yours is electric (look for an electrical connection to the gold round actuator attached to the turbocharger) then check to see if Nissan has processed your vehicle for the recall. If it has, then your actuator has possibly died (it'll be the first one I've heard of but I never say 'never' ). Examination of boost levels will tell the story there.

The other error is odd but if the turbocharger isn't able to boost properly there's a chance that the exhaust isn't going to flow predictably (in terms of numbers the ECU is expecting) and it throws 102b.

However, another alternative exists: poor electrical connections and the first place to look is the battery. In the 2011 model I'd also check the earth near the ECU, Nissan didn't remove the paint when they installed the earth screw and sometimes it was okay, sometimes not. Clean it, reattach it and spray it with battery terminal sealer (or even nail polish, you just want to keep the air off it).

 

[Hazlow]

So I've tried cleaning the contacts and the actuator seems to work properly. The issue is still intermittent but I've noticed it only occurs when the engine has warmed up.
When the code has been cleared it runs fine.

Could it potentially be a sensor?

 

[Old.Tony]

So I've tried cleaning the contacts and the actuator seems to work properly. The issue is still intermittent but I've noticed it only occurs when the engine has warmed up.
When the code has been cleared it runs fine.

Could it potentially be a sensor?

There's always that possibility, but I bet you paid less to clean it up than you would have to buy the sensor.

The crime is suggesting that you replace the sensor and it doesn't work until you clean up the connections, that would make me feel like a real mongrel.

There's no harm in popping the sensor out and examining it and then putting it back in. Check the earth to the exhaust too.