Throwing a P0047 OBD Code

[Horus]

Heya all... The welcome gift from my new 2016 GUN126R today (after one day of owning it *sigh) was limp mode and a very poor drive home. This was presented to me with the Check Engine and Slip lamps showing, and the ever-useful warning to go and see my Toyota dealer *rollseyes

I have a wireless OBDII dongle that seems to work well with Torque OBD and has thrown me a P0047 (Boost Control Solenoid "A" Circuit Low). I cleared it but it keeps coming back and dumping me into limp mode. Is anyone aware if anything else can present like this or common things that may do this. I'm guessing I'm off to get a new boost control solenoid to swap it out, but I can't find a good parts break down so if anyone knows the part number required that would be awesome.

I keep finding 14956-EB70B but unsure as it's not pointing directly to my model which is a 2.8L Diesel, 2016 (1GD-FTV). Thoughts?

[Horus]

Today I had a crack at diagnosis, I still have a permanent P0047 code and running in limp mode. I pulled the bigger plug off the turbo vane control stepper motor (3wire closest to camera), and it threw another code (P2564), when I placed it back again that fault code disappeared as expected. I then removed the smaller plug from the same unit (2wire further from camera), and there is no change at all... No extra fault codes and the same code remains so this is where my focus is right now.

Logically I can go through the following in my mind; Boost ECU behind the glove box poked, vane operation jammed up, faulty stepper motor unit, or no power to it via the 2wire plug (didn't have a multimeter tonight to check).

Questions; Does this stepper unit have a fuse and where is it, have I not considered anything, what would be your next step if you were me?

[Horus]

I'll keep a record here at least, maybe it can help someone by the time I'm done.

Tonight, I measured the 2-wire voltage with the engine running, 0.4v on the Green wire, 0.54v on the White wire, not much, bearing in mind the vehicle is running in limp mode so this may only be the default stepper drive voltage from the ECU in limp, unsure, but thinking it having voltage at minimum is a good thing as it proves connectivity at the least... and hopefully that the drivers in the Boost ECU are OK. So really, it's just seeing if the variable nozzle is mechanically free and easy to prove the stepper is at fault now. I think?

I'm assuming when the stepper motor or mechanical side at least gets tuff to move and causes burn outs on the drivers in the Boost ECU working too hard (some have reported), I can only imagine it drives the stepper with 12v and not a 5v signal over the 2-wire like most motors  of this type in a vehicle, and that polarity is switched for direction in the Boost ECU over these too (total assumptions at this point but have no other bearing so far).

I may have a spare stepper coming my way to plug the existing wiring into to see if the P0047 disappears so that should be a good test to prove it if I can get my hands on one, I think that would make sense, but that's not to say at that point it could still be mechanically ceased and will have to check this too.

Any input from anyone would be appreciated, bit out on my own here which is why I joined the forum - So if you know anything, please feel free to chime in.

[Horus]

I'll keep a record here at least, maybe it can help someone by the time I'm done.

Tonight, I measured the 2-wire voltage with the engine running, 0.4v on the Green wire, 0.54v on the White wire, not much, bearing in mind the vehicle is running in limp mode so this may only be the default stepper drive voltage from the ECU in limp, unsure, but thinking it having voltage at minimum is a good thing as it proves connectivity at the least... and hopefully that the drivers in the Boost ECU are OK. So really, it's just seeing if the variable nozzle is mechanically free and easy to prove the stepper is at fault now. I think?

I'm assuming when the stepper motor or mechanical side at least gets tuff to move and causes burn outs on the drivers in the Boost ECU working too hard (some have reported), I can only imagine it drives the stepper with 12v and not a 5v signal over the 2-wire like most motors  of this type in a vehicle, and that polarity is switched for direction in the Boost ECU over these too (total assumptions at this point but have no other bearing so far).

I may have a spare stepper coming my way to plug the existing wiring into to see if the P0047 disappears so that should be a good test to prove it if I can get my hands on one, I think that would make sense, but that's not to say at that point it could still be mechanically ceased and will have to check this too.

Any input from anyone would be appreciated, bit out on my own here which is why I joined the forum - So if you know anything, please feel free to chime in.

[Horus]

Tonight, I popped the circlip off the armature to free it from the stepper and confirmed the vane adjustment to be free and easy so thankfully, the turbo is mechanically sound as far as I can tell with no restrictions in its movement of the armature, I now feel confident the fault is 99.9% the stepper motor only so I'm ordering this tomorrow. Shop around, these are ridiculous prices in some places and something you can swallow in others. Found an aftermarket replacement with 3 year warranty roughly 3 days away from delivery from me for AUD $389.00 delivered... It could be worse.

I'll post up how changing that over goes when it happens and hopefully with some good news that I'm out of limp mode with the problem, and fault code gone. This change over can apparently be done in place without removing the whole turbo so with any luck it may only take an hour or two to replace. If anyone knows a good write up for this or a YouTube link of someone doing one, that could be helpful. Watch this space I guess.