Hello all! I'm new to this forum and badly in need of some good advice on my situation. Last week I was in a minor accident where something fell off a truck and I swerved to avoid whatever it was but it still went underneath my 2007 RX400h, causing me to go off the road into a dirt/gravel ditch. As a result, the front driver side wheel blew out and I noticed that the factory rim was bent as well. I was able to pull back onto the road and then the shoulder, but noticed the P/S light on and my truck was incredibly difficult to steer. I had it towed to a garage the very next day where they ran a diagnostics test and came back with the following:

-POWER STEERING SYSTEM
-C1568, DC TO DC CONVERTER.
-C1241,TOO LOW OR TOO HIGH BATTERY VOLTS.

Can anyone tell me what these codes mean and would this be an easy fix? I purchased "Pearl" less than a year ago and for her age, she's in pristine condition, one owner who took excellent care of the vehicle and it was never in an accident until now. The garage who performed the diagnostics mentioned they don't have the tools to work on my hybrid (strange) and suggested that I send it straight to the dealer to fix it. That is and absolute LAST option as I know the prices will be insane for parts & services. I had it towed to another "in-network" garage, only for them to take a look and see that the engine cradle is broken and said I'll need a new gear assembly, as well as an alignment. Mind you, garage #2 never even put my truck on a computer for a full diagnosis!!! They put it on a lift and discovered the later damages and came back to me with a ridiculous parts & labor charge of $6K!!! I only paid $10K for the truck cash and Liberty Mutual is basically telling me that the car will need to be totaled out. While I don't mind getting a new truck, I have become a bit attached to Pearl and put a nice amount of $$$ into her prior to the accident. Liberty Mutual is not gonna cut me a check for $10K either. Is my issue fixable? Can it be done for less than $6K??? I'm completely SICK behind it all. And all this happens right as the weather starts to break.....UGH!!!Sorry about the long paragraph but I just wanted to be as detailed as possible. Any sound advice is appreciated.....

 

have you googled the codes? damage to wiring/connectors will cause these codes. i would be doing a close examination of all wiring under the car.

 

I did google both codes and got mixed info on the c1568 code, but it says DC TO DC CONVERTER. the c1241 code is low batt positive voltage. sounds like something as simple as the battery or a bad fuse maybe? This is my first RX, first SUV period. I guess I should ask has anyone ever done the work on something like this? anyone ever had this type of work done before? parts and maintenance at the dealership? I really don't want to lose my truck....

 

https://www.clublexus.com/forums/hyb...g-battery.html
https://www.clublexus.com/forums/rx-...us-rx400h.html
https://www.clublexus.com/forums/rx-...indicator.html

 

Hi wiggz, you need some real answers.

I just spent an hour pouring over the schematics and how the hybrid electrical is stitched into everything on the car including the steering, brakes, engine, skid control, body electric, etc and it's way too complicated for anyone but the dealer or an indy or an expert dc technician for this code in my opinion.

You may get lucky and it just knocked a connector loose somewhere or knocked a ground wire off and can be spotted by looking over the car well or maybe a lucky chance the codes will reset by unhooking the battery for a few mins. Everyone needs a lucky break once in a while.

Chances are it may be a simple fix, too early to tell but I'd have someone you trust(not a shop) look around the area of your electronic power steering for a broken wires or connector. Your bent rim & flat tire are in close proximity to damaging this area.

Someone with Techstream may be able to do a Live Active Test on the steering by moving the wheels from a laptop and rule many things out fast. If you only damaged the electronic steering rack, this is not a $6,00 fix but you need someone you trust to look at it,

Chase these possible fixes based on the code thru the schematcs and you will see what I'm saying.

 

until you do a full detailed inspection under the car looking for wiring damage, you are wasting your time looking elsewhere. You have damage to the car that points to likely damage to wiring under the car.

 

Peace Margate330.

Thanks for your response and your time spent researching my issue. These damn Lexus hybrids are indeed one complicated specimen!! It's no wonder garage #1 wouldn't even touch it after performing the original diagnostics that produced those codes. They recommended me straight to the dealer. Garage #2 never even had a mechanic/technician perform a diagnostics, yet the mechanic came back with other issues, stating that the engine cradle is cracked or broken and that I need to also replace the gear assembly on the driver side tire where the rim was bent. I figured there had to be some damage there as well, but STILL, none of the above sounds like $6K worth of parts and labor, especially not at a local garage! Let's keep in mind that my car is 15 years old, so I'm assuming the engine cradle was already old and a bit rusty when I purchased the truck almost a year ago, as the chick at garage #2 stated. First it was cracked, then she comes back saying it looks old and rusty?? Something's not adding up and it's just sending up red flags on my end. The originally tried ordering powering steering fluid for my truck, thinking that was the issue, not knowing that the P/S in this particular model Lexus doesn't take power steering fluid.....like HOW SWAY??? This was yet another red flag with me that my car is in the WRONG hands. They ran up $6K worth of parts and labor without even testing the heart of the vehicle and that's not sitting well with me. But, from the sounds of them saying that I need a new gear assembly and and alignment (obviously), those two alone point to 1. on that list (Power Steering Converter). It doesn't look or sound as if the Hybrid Control System was damaged, yet only someone trusted with this type of knowledge should be looking at it to make a more accurate decision as you originally suggested.

I was just beginning to fall in love with my RX and still getting familiar with this model until this happened. The system seems far too technical that it's almost deterring me from coming back to another one especially if the insurance company finally deems it a total loss. I've owned the ES300, the LS400, a badass LS430 on Twinkies (loved that ****in car!!!) and decided to step up on the truck side with Lexus, but it seems to be more of a pain maintenance-wise, especially if a wire or something gets tripped or knocked loose from a rough pothole. I'll just have to wait until Monday till I can get it to the dealer and let them determine the fate of Pearl. With only 140K on the dash, and zero body damage, pristine leather and cabin, she's practically a brand new truck for her age. I just refuse to give up on her that easy. I'm sure some of you feel my pain. Once again, thanks and sorry for the rant.....

 

If the gas engine runs well we can rule out all that especially since you have no EFI codes.
If the car drives down the road we can hopefully rule out a broken front trans axle.

In the area of the flat tire & bent rim on front driver side and your testimony of being hard to steer- that only leaves a couple things- broke connectors, wires, and electrical assist steering rack/bent tie rods, etc. Unles when you went off side of roard you hit something under car in another place.

From the code list as one can see it is not exhastive and assumes a normally running car(not wrecked) and is kinda funny how broad the description.

1) Power steering converter: I believe this is also called the DC/DC converter in the scrematics/repair section(steering, not hybrid battery section).
2) Hybrid control system: covers practically everything on car since it's stitched into everything electrical in one way or another.
3) EPS DDC Fuse: I can't find this fuse in any schematic so I think it may have another name for reference maybe but could be worth looking into.
4) Wire harness or connector: Like tom51 above I agree, I'd look in area of bent rim(check wheel sensor too if hybrid has one).
5) Power steering converer earth wire: this is located in rear of car nowhere near the front bent rim.
6) Power steering ecu assembly: juking the steering harsh from external force can in theory send a voltage spike backward thru the circuit damaging the ecu(just in theory).

 

Margate330, you are ON IT my man!!! Your breakdown and diagrams are exactly what I need in my current situation. Even though I'm new in the RX world, your homework on my issue is helping me understand exactly what it is that I'm dealing with, especially with this being my first hybrid vehicle as well. And as it stands, I'm only going to feel comfortable with Lexus professionals giving my vehicle a proper diagnostics. As you stated, it doesn't sound as complicated as I thought unless something hit and damaged the Hybrid Control System, but I don't think that's the case. That indicator never flashed or came on in my vehicle. Only light that popped on my dash after the car slid to a halt is the P/S light. I was able to stop and start my car several times with no issues and shift into all gears with no issue as well. I have made an appointment with Lexus of Annapolis for Monday and will keep my fingers and toes crossed and pray that they don't come back to me talking about $6K worth of damages and repairs! With my vehicle being as old as she is and not under any type of warranty, I can be up ****'s creek is something else this drastic happens in the future. May need to seek an alternate company that offers warranties on used vehicles. It couldn't hurt. I just came back to Lexus after a few years of getting rid of my LS430 because of computer problems and issues with the VCU. The reunion has been bittersweet thus far.

Thanks again my friend!!! I'll be sure to keep you posted on what the dealer says. It sounds like you may have pinpointed exactly what my issues are with those codes. It's only right that I follow-up with you because of your diligence. I owe you that much Sir!

All the best,
Wiggz

 

Peace Margate330! Hope all is well on your end!

My RX400H has been with the Lexus dealer since Tuesday and so far, searching the codes that I gave, they checked all of the fuses per the diagrams that you provided and discovered that the Main Fuse is blown. They had to go in the back, take out the seats, etc. in order to discover this. They didn't mention anything about needing a power steering assembly like that other garage mentioned, so that's good news to my ears. Apparently the converter or computer is still good because no error codes there or anything pointing to that....another small victory. My question is, once the new fuse is put in and the vehicle breathes new life again, will this hopefully bring the power steering function back? I'm still amazed at the intricacies of this Lexus hybrid system. As you mentioned before, when I went off road, I'm sure the harsh juking of the wheel to regain control of the vehicle and the external force caused the voltage spike and blew that main fuse. Hopefully this fuse will be the solution to my current worry and headache. Anything else that you can share that they might want to test or look for after the fuse arrives in the next day or so would be appreciated my friend!

 

Hi wiggz, this is great news.
The electric power assist will not work with that fuse blown so hopefully it's done and fixed!

I was able to find a little more info digging thru my other drawings and hoping for your success but you are not in the clear yet but looking in your favor.

Here is the Path:

1) The power for electric steering comes directly off the DC bus from the hybrid battery thru relays(see below). No way in gods green acres did you damage the hybrid battery, all good there.
2) Hybrid battery powers all 3 of these relays and they power other things in the hybrid system too. The Fuse in the pic below must be the DDC fuse because it only goes to the steering and it's blown.
3) These relay coils are controlled by the Hybrid Ecu, should be ok there.




4) Ok so power arrives at the power steering converter and is then sent to the power steering ecu after a possible voltage level change. From here it is obvious the electric steering motor is a 3 phase brushless DC servo style(or equivlent) because I can see the "U, V, W" wires going to the motor. The power steering ecu is acting like a motor driver from what I can see.





5) Here is where things can take a turn for the worse but I think you may be ok. There are 2 CAN communication wires going from the power steering ecu making a loob back to -> You guessed it lol the hybrid ecu...





One last thing, I would make them check every darn fuse on the car. I found another fuse labeled DCC-S- haven't had a chance to chase it out but may not be related to steering.




PS- Since you blew the fuse upstream from the power steering converter you may have some damage. Looking at this deeper it wasn't voltage spiked. The power steering ecu appears to over current from juking the wheel against the motors max stall torque. That fuse may have saved the day from frying both the converter and the ecu. Looking forward to your report.

Plz keep us posted!

 

Looks like i just bought OP starter's car . Found this RX on Copart yesterday. It's been listed as a salvage title so i'm assuming they ended up totaling it. After checking vehicle's history at drivers.lexus.com i started googling fault codes that dealer provided when they diagnosed it a few weeks ago and couldn't believe when I came across this thread. Now that's some Sherlock Holmes ***** lol. Anyway i don't have the car yet, should be here sometime tmw or Friday.
Here's what the last service record shows: " ALSO GOT A DIAG DONE AND HERE ARE THE CODE BELOW- C1568 C1241-TOO LOW OR TOO HIGH BATTERY VOLT-KLE ~|~MAIN FUSE BLOWN ~|~TECHNICIAN REPLACED THE MAIN FUSE. STILL NEEDS A DC CONVERTER". So they're suggesting a new DC converter after all. Will see when it gets here. I may still need some help diagnosing it so please don't kill the thread

 

I'm sad for the OP if they totalled his car but I'm glad someone bought it and didn't go to the salvage yard to get parted out and crushed.
If they kept to their word and replaced the DCC fuse as mentioned above then you should be getting power thru the "main relay aka power steering relay" to the Power Steering Converter aka DC/DC converter.

>> This may give you a boost and place to start.

OK, Hybrid battery DC voltage should be measured at 2 wires at Power Steering Converter as seen below:
Wire 1: CBP, Pin 1, Red, connector P45(C)
Wire 2: CEP, pin 5, Blue, connector P45(C)

>> Please be careful because this may be high voltage and if so plz confirm for us what voltage to expect here from your tests.
>> Main Relay is controlled by Hybrid ECU so hopefully see no voltage when key is off to make safe to remove if necessary and see voltage only when key is on.







PS- I recommend getting techstream ASAP since you don't know yet how deep this repair will go and If you pull the PS converter plz post pics and splay the guts inside so we can see(if you can do it safely)- may get lucky and be repairable.

 

Finally got the car few hours ago. I was able to check a few things before it got dark outside. DC converter gets 300V coming in, yet it puts out 30V(white plug) which doesn’t seem normal, right? So I guess that at least puts the fuse off the table? I then took apart the converter and as you can see no smoking gun there. Checked the wires underneath to make sure nothing’s damaged. The only things that took the beating are the rear control arms and shocks but that could’ve been done by a forklift at the auction. I don’t have tech stream but I took some readings with my autel. Do you think that dealer was right about dc converter? Should I run any more tests? Is there a possibility that ecu can be bad as well?

 

Good job!

Ok one step at a time and straight thru this hopefully.
I was worried about a safety risk of High DC Voltage on those 2 wires mentioned above and you just confirmed it.

>> For anyone following your work in the future can you tell us if the voltage goes to 0V(off) across the 2 wires when key turns off and confirm?
>> Does the car start up and run normally with no issues including a good & proper voltage from auxillary battery?


Hybrid owners- if you know what the normal working voltage of the Hybrid battery should be please post so we can be sure we aren't working with a run down battery.

PS- this looks like it is converting the high volt DC Hybrid battery down to a lower DC voltage. So to answer whether 30V is good or not I need to dig in and see if I have any info on this or maybe someone else does and can post. Just in theory there may be nothing wrong with this unit since you are receiving voltage in and voltage out. I will need to try to deduce whether this unit is Hybrid ECU controlled thrus controlling the PWM output voltage.

>> Plz post the voltage and markings on this Blue Capacitor