2006 RX400H.... HELP! ENGINE TOTALLY DIES WHILE DRIVING!

[BritRom]

Any help gratefully received...   I have a 2006 RX400h.  130,000 miles.  4 months ago, I was running 72mph on the interstate and the whole car shut down - shifter, engine, lost steering, EVERYTHING!    Read several reviews, I changed the regular battery under the hood, everything re-set and all was well for 5,000 miles.   Now it has just happened to me again twice within 2 weeks. 

The new battery is only 4 months old.  I guess something could be draining the 12 volt battery, but is it possible that the hybrid battery could already be bad?   What codes do I need to be looking for?   Don't want to be taken for $1,000s of dollars needlessly...  

Any help or advice gratefully received. 

Thank you! 

[RX400h]

There have been some complaints over the years but this site's severity rating is a 2.

14 Complaints: 2006 Lexus RX 400h Power Train Problems (carcomplaints.com)

I have not seen many similar complaints in this forum. Did you scan for codes?

 

[BritRom]

Hi there, 

Thank you for your reply.  I believe I found the problem - my RX400H is currently at the dealership for a recall.   Copying and pasting below, a post to the general forum, that I hope is a help to anyone else who has a used 400h and has not checked into this!    Thanks again.  

----------------------------

THERE HAVE BEEN TWO MAJOR RECALLS  RELATED TO THIS PROBLEM.  The first in 2011, the second in 2013.  Both are related to the inverter module inside the hybrid system.  IT IS A SERIOUS PROBLEM!   

So, if you are like me and have an older Lexus hybrid, I advise you to call your Lexus dealership REGARDLESS OF WHETHER YOU ARE HAVING THIS ENGINE DYING/SYSTEM FAILURE PROBLEM OR NOT!    Ask if your vehicle has ever had this recall done.  All they need is your VIN number.   This recall DOES NOT EXPIRE!!!

Take a look at this link and it explains everything in more detail:  https://www.cars.com/research/lexus-rx_400h-2006/recalls/ 

I hope this is a help to someone!! 

God bless you and stay safe. 

[RX400h]

I hope that fixes the problem. Please let us know how it turns out.

[DrRocky]

I have a 2019 RX450h with 15,000 on it.  Had a year.  Twice system has died-just as described above.  When I get to dealer (message says visit the dealer) and turn engine off, it resets.  Dealer says nothing wrong with car (don't you just love it!)  Had a 2015 RX450h that I swapped in--big mistake!  Had 120,000 with no issues. Help.  What do I do??

[RABeyer]

My 2006 RX400h (purchased pre-owned in 2008) stalled and shut down, just as described above...Orange 'check' engine symbol was in left side dash and 'Check Hybrid System" with "!" in Red triangle was in center dash. I lost acceleration and steering, though indicators (powered by 12v accessory battery) still worked ! Local mechanic scanned system and was shown "Lost connection to hybrid battery" message. It's beyond his scope of work on hybrids, so I'm now waiting to hear from dealership service, as I'm afraid to drive it (losing steering with no way to restart without turning off and back on was not safe). ANY information greatly appreciated. It's been a well maintained and great vehicle all these years. 

[RX400h]

Have you reviewed the information in the third post?

[rhkwon]

I believe in addition to the recalls, the 3 cooling fans for the hybrid battery are prone to failure.  When one or more are no longer working the battery is not able to be cooled properly. Thus, the battery will quickly lose power especially under hard continuous acceleration.  Given the cars are now over 15 years old (think of how many revolutions those fans have done), the fans need to be replaced. 

My light came on one time and the scan showed a P3015 code. The dealer had previously performed the recall as well as fix a loose pin to the ECU.  I reset it but of course it came back after the incident described below.

I also had a similar situation on the freeway.  I accelerated very hard several times and then noticed the battery charge was down significantly.  Soon after the car lost all power and I had to cruise off onto the feeder.

You can DIY to replace the fans or take it to the dealer for about $1,000 to $1,500.  

[RX400h]

The first thing to do would be to have the dealership scan for specific codes. The "Check Hybrid System" and "Check Engine" warnings are generic; they don't pinpoint the cause. That's good to know about the fans. Thanks!

Our RX400h has over 130,000 miles on it and has not required any non-maintenance work.

[Barfkity]

Hello RX400h owners.  I have a 2006 RX400h with 116k miles on it.  It is in very good cosmetic condition and I love it!

I recently had this issue - vehicle shuts down while driving but then restarts and drives perfectly.  Dash lights up with the "Check Hybrid System" warnings.  The intermittent nature of the problem made it "feel" like it was an electrical short or something.  Of course it is scary because the vehicle shuts down while driving and could cause a wreck!  It means that we don't have confidence in our vehicle for long trips, etc.

I ultimately replaced the cooling fans and the relay pack inside the hybrid battery.  It seems to have fixed the issue.  I have been driving the vehicle for a couple of months now and have had no recurrence of the issue. 

I did the repair myself, so I thought it would be useful to post a description of the DIY.  It was actually very easy to do.  It is a complex job - there are lots of steps - but each step is easy.  If you take your time and make sure you put all of your parts in an organized pile, it is easy to put the vehicle back together.

I think that there are many shops out there - including the dealerships - that would be more likely to tell you that you need to replace the entire hybrid battery for $2200 (used/reconditioned) or $4000 (new), or more.  This is a good DIY repair.  I would go so far as to say that it might be a good preventative measure to take once your 400h gets to be older with higher mileage.

First of all, I agree that the first step is to get your vehicle checked for any recalls.  Mine had the inverter recall done by a previous owner, so that was not a problem.  I also agree with the idea that if the 12v battery is old, replacing it is not a bad idea - they do seem to be undersized and really only last about 3 years in these vehicles.  When they get old they can contribute to electrical issues.

So, I had a similar experience to RABeyer where a local mechanic had scanned the system and found "Lost connection to hybrid battery" message.  There's a simple ECU inside the hybrid battery that "talks" to the main ECU under the dash.  When those two lose connection, the hybrid system shuts down.  Then we limp our vehicle over to the side of the road, turn the key off and turn it back on and, presto!, the car runs perfectly again.  That's because the communication issue between the two ECUs is intermittent.  If your vehicle has exactly this problem, then replacing your cooling fans may fix your issue - and if you do it yourself it may only cost you about $400.  By the way, my understanding is that the problem is not caused by the fans failing to cool the batteries, but is caused by the fans getting old and causing electrical "noise" in the system due to electrical resistance in the fan motor. 

These video is long but it explains the issue in detail:  

 

So, the repair involves:

1. Remove back seats.

2. Open hybrid battery pack.

3. Remove and replace the three cooling fans.

4. Close hybrid battery pack.

5. Replace back seats.

 

I used these videos to do this repair: 

and 

 

So I attached some pictures.  Battery Pack shows what the battery pack looks like when you take out the seats and lift the carpet.

Back seat shows what it looks like when you take the lid off of the battery pack.

Organized shows how I had my car parts laid out in my garage.

3 Fans shows the fans that you will replace.  They are the three snail-shell shaped items along the back of the battery pack (along the left in the picture).  They simply unplug from the harness and are held in by 3 screws each.  Really simple remove/replace job.

Relay Pack shows the high voltage relay pack inside the hybrid battery.  I went ahead and replaced this, as well.  It looked like it was in good shape, but relays can wear out internally.  I figured that I would go ahead and replace this while I had the car taken apart.  I don't think this was actually necessary to fix the issue, but it only cost about $400, so I just figured it was a good preventive repair.  This was also easy to swap, just unplug the connectors, remove it by taking out 3 bolts, plug in the new unit, and bolt in the new unit.  

Parts is just the boxes that I received from Lexus.  I was able to buy brand new parts from the dealership and have them shipped to my house.  Since you are replacing electrical components, I think it only makes sense to use brand new parts.  If you put in rebuilt or used, you may be just replacing bad with bad.  The fans were part number G923048010 and were $110 each.  The relay pack was part number G384048010 and was $330.

So, if this is your problem, this is an easy fix.  I did not need any specialty tools.  I mostly used a simple ratchet and sockets.  I did have an electrical tester and I did follow the instructions in the videos to make sure the high voltage system was safe to work with.

[RX400h]

Thanks, Aaron. I have pinned this topic for ease of access by other members.

Dave

[Cathy S]

I have the same problem with my 2008 Rx400h. Took it to the Lexus dealer in Kingsport, Tennessee and they claim it's a defect in the "gutter" drainage design and that water gets into the hybrid system, hence the "Engine Check" light displays check hybid system.

We contacted Lexus headquarters in the US and they responded with it's "not anything we can do about it", basically saying tough luck! This is a dangerous and potentially catastrophic situation if the vehicle dies suddently on a freeway putting passengers in peril. I cannot in all honesty sell the car as it is, but I can't spend $8,000 to repair it as they estimated. 

My husband is an attorney in Florida and is willing to open a class action suit against Lexus to get them to repair or replace all defective vehicles and NOT put people's lives at risk each and every time they get into their vehicles.  If anyone is having a similar situation, you can call his office at 954-764-7600 ext 303 and perhaps together we can put pressure on Lexus to own up to this horrific defect by doing the right thing for their Lexus car owners before one of us ends up in the morgue!

 

[rhkwon]

I just replaced the cooling fans. These are just a few helpful tips that I would like to pass along. Replacing the fans took me 2 days as I took my time and took a lot of rest breaks  If your are serious you could do this job in a couple of hours.  The 3 fans cost me $300 and I saved about $1000 in labor.  You will need assorted extensions and 14, 12 and 10mm sockets  

1. There is no need to disconnect the 12v battery in the engine compartment. Just make sure you unplug/disconnect the main orange shut off switch on the passenger side of the hybrid battery. I did not need to wear electrical gloves but I did anyway just to be extra safe. They can be cumbersome but especially worth it when lifting up the top cover as it will prevent cuts.

2. Taking out the back seats is not complicated but a time consuming process so keep that in mind.  Move the front seats forward as much as possible. Remember to cover the metal  seat rails with tape so that it doesn’t scratch the plastic sills and sides of the car. Or just be extra careful when taking the seats out of the car. I made this mistake and scratched the inner plastic covers but thankfully when the seats are back in will be covered up. 

3.  Use interior trim removal tool to lift up the black plastic clips. Much better than having your fingernails lifted. The sides of the rear trunk trim behind the seats are a 3 way process. Each end of the piece is secured by velcro. The middle part is secured by white plastic clips. Use a big flat tipped screw driver and lift up one clip at a time. 

4.  When the seats are out vacuum the carpet and lift it up and lay against the front seats. There is no need to take off the side door sills or the rear inner plastic covers as mentioned in the Youtube video. Just carefully free the carpet from beneath the plastic. 

5. No need to disconnect any electrical connectors or even the 2 orange plastic plugs on the cover. Just remove all the bolts and the cover will lift off. Also remember to disconnect the center seat belt anchor. There is also a bolt that anchors an electrical connector underneath the center panel so make sure to undo the bolts to that center cover (this cover has the tape on it)

6.  After removing the cover replacing the fans is easy. Undo the 3 10mm bolts to each fan. Disconnect the connector and pry out the connector plug using a small flat tipped screw driver.  When inspecting the fans they looked good to me and had minimal dust but keep in mind they are over 15 years old and have spun many millions of revolutions  They also have a green circuit board underneath the fan  Remember the job of these fans is to keep the battery cool  Others saying it is not that they are keeping the battery cool but the communication issue imo is not correct unless the circuit board is malfunctioning  

7.  Take pictures to keep track of where bolts go. 

This is a tedious job but not complicated. I’m glad I did this because now I am enjoying my 7 second 0-60 runs which I could not do before 😆

[rhkwon]

Correction the orange safety plug is on the drivers side. 

[Will A]

On 2/22/2021 at 8:43 PM, BritRom said:

Hi there, 

Thank you for your reply.  I believe I found the problem - my RX400H is currently at the dealership for a recall.   Copying and pasting below, a post to the general forum, that I hope is a help to anyone else who has a used 400h and has not checked into this!    Thanks again.  

----------------------------

THERE HAVE BEEN TWO MAJOR RECALLS  RELATED TO THIS PROBLEM.  The first in 2011, the second in 2013.  Both are related to the inverter module inside the hybrid system.  IT IS A SERIOUS PROBLEM!   

So, if you are like me and have an older Lexus hybrid, I advise you to call your Lexus dealership REGARDLESS OF WHETHER YOU ARE HAVING THIS ENGINE DYING/SYSTEM FAILURE PROBLEM OR NOT!    Ask if your vehicle has ever had this recall done.  All they need is your VIN number.   This recall DOES NOT EXPIRE!!!

Take a look at this link and it explains everything in more detail:  https://www.cars.com/research/lexus-rx_400h-2006/recalls/ 

I hope this is a help to someone!! 

God bless you and stay safe. 

I have this same problem exactly in fact identical towed it lexus dealership first the said had water in the vehicle replaced the electric block that shorted out car started back up took it for test drive an after 3 miles stalled again been in shop for 2 months now coz they dont know whats wrong . Mentioned the ipm recall of 2011 and 13, but said they cant find that recall in there system. Im frustrated please help any suggestions?