asampson

I did actually see this and have an e-bike that I could do it to but he unplugs the power steering converter and then how does he jump the ECU it doesn’t really explain it the best to what pins exactly.
also I did see a post about the resistance on good and bad modules my original reads about 1.2ohms the new one from breakers reads 0.2 so going off that it’s saying both are bad lol .
I do want to do the e-bike way but not sure how

Margate330

I believe he unplugged the Power Steering Ecu from the DC/DC converter and then applied +42V to P47,Pin 1(white) going to the Power Steering Ecu, plz see post #1 above.

Also, for anyone following along, please see post #23 here: https://www.clublexus.com/forums/rx-...d-c1241-2.html

As mentioned in that post, if you have low ohms(shorted or near shorted) on the power inputs on the Power Steering Ecu, she's smoked lol, need to find a good unit.
>> If you open it up and it smells smokey and toasty, it's probably junk.

>> Battery is unhooked for this test to make sure you have no voltage present when doing an ohm reading or you can do the test with the Power Steering Ecu completely unplugged.

Power Wires for Power Steering Ecu:

asampson

Right Ok sorry not been on here have been waiting for a new ECU to come and all seems ok. I have plugged in and same fault still there with DC-DC converter 😔.
i have taken battery off for around 20 mins and reconnected and still showing same faults I have posted pic.
I know the dc converter is ok as I have placed the 12v in the p41-11 plug and got 42v back.
the problem I think lies in 2 things one the ECU is telling it not to send the 12v down the lead to start for whatever reason.
the other is on my scanner on live data feed there is a feed that says DC-DC warning signal STOP and I feel like watever it is saying stop is the reason ECU is not sending that 12v .
would love some feedback from anyone and of course MARGATE who has been so helpful.

PS - I checked the voltage from the main hybrid battery at the blue and red leads going into the converter so we know it’s not the DDC fuse.
I haven’t been able to get a 42v battery but hopefully can do today to see if that works

Margate330

Yes please!
If anyone knows some info on this please jump in!

I believe the first two codes need to be done after you have control of the steering so I believe the DC/DC code issue needs done first, don't quote me, just a theory.

That wiring list you posted above answers some unknowns on two wires that we now know are DC/DC error signal wires.

DC/DC Converter, Error wires:
Yellow/red: what is the voltage?
Red/white: what is the voltage?

It would be awesome to document this especially if an error wire can be unhooked to bypass an error, just for troubleshooting and to see if the DC/DC converter starts working, at one's own risk of course.

asampson

Yeah so I do believe when the dc dc converter error is cleared it will allow to recalibrate everything.
I have just checked the 2 communication wires and the voltages are 4.2v on both give or take.
Also the can high and can low are showing V of 2.4 give or take again.
its just this dc dc warning signal -Stop
that is really killing me

Margate330

The high speed CAN bus wires are on a data bus shared with other components.

You are communicating with the Power Steering Ecu so I believe you can rule those wires out

Congrats, we are digging deeper into the system and I believe you will figure it out

We can't assume the DC/DC converter is good until everything works properly.

As you saw in that last thread, dealers are totaling these cars when the diagnosis gets to this level.

The error signal wires may be the key, when fixed in hindsight

asampson

Do you know if the power steering ECU needs coding to the car as I’ve seen somewhere else it doesn’t but just run a check on computer and came up saying one unit doesn’t match vin number?

Margate330

I don't think so but I don't know 100%- if he did code a vin either he forgot to post about it or I missed the post.

Referring to the other thread, he had a couple of bad Power Steering Ecu's in a row bought used.

His DC/DC converter was also proved to be damaged junk. It would put out the voltage but failed under load when turning the wheels.

From best I can tell, once he had a good DC/DC converter and a good Power Steering Ecu, steering was back and he had to do a "calibration" procedure, probably to clear the code and make everything happy.

He proved the DC/DC converter faulty by unplugging it from the Power Steering Ecu and injecting the 42 volts DC directly into the Power Steering Ecu
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Margate330

It's not clear on the wiring list you posted but error signal wires implies binary to me.

Maybe high(+5v ish) means error and low(near 0v) means good?

Im referring to the red/yellow and red/white wires.
I don't think these wires carry any data, at least in theory by how it's described as "error signal wires".

If it was my car I would unhook them and see what happens but it's not my car so if anyone does this, do at own risk.