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Hi all,

Hope everyone is well, and thanks in advance for any assistance people can be.

Over the past two days my 2013 is300h has been intermittently throwing the EPS Failure. Steering wheel harder to turn fault.

 

It then a few moments later goes away and the steering wheel becomes light again, then randomly later on while driving it will pop up again then go away etc etc etc. Of course when it comes up the car becomes like a bus and the wheel is very heavy.

 

Anyone have any ideas on what could be causing the intermittent fault, I can drive for miles and it will be fine, or 5 mins and it happens a few times.

 

Thanks once again,

 

 

James

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I had something very similar with an RX450H that my wife had . As you say it was like driving a bus - in fact it was undriveable when it did happen . I had to switch off and start up and it would usually disappear for a short period but returned again soon afterwards . Ended up getting towed to Lexus dealers and they ran some software update or something similar , charged an hours labour and it never came back . Mind you it was very dangerous when it did happen and she had lost faith in it so we got rid of it . Shame really since was otherwise good to us . It had relatively high miles of around 120k when that happened . Hope that helps because the alternatives I was thinking of involved new steering rack at from memory around £2.5k so for once I was actually happy that dealer did not suggest that - a local independent had suggested that might be required . 

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Is/Has it thrown an EML? and if so an error code will be stored and can be interrogated.

paul m.

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No EML, just comes up on the dash with the steering wheel light an the error on the main dash screen, it seems to be doing it a little more today as well, I wonder if the motor is on its way out.

 

Going to get under the car over the weekend and check the rack out, motor, connections etc.

 

Theres some used racks off salvage cars on ebay for sub £200, not as bad as 2.5k i guess lol

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Even though there are no warning lights there may be a code stored in the ECU memory, by all means have a look underneath but from there I would get a diagnostic check done. I had the same problem on my Vauxhall Vivaro van and that was a software update requirement.

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Hi All,

 

Little update, the car also comes up with voltage abnormality steering harder to turn warning as well.

 

I got hold of techstream and plugged into the car, when the EPS warning light is on techstream can’t communicate with the module, when it’s not warning I can read the EPS module but there’s no code.

 

Any thoughts? Dying eps ecu?

 

thanks

 

James

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Colin is the man for this problem, his hybrid knowledge is second to none. I’m old skool hydraulics when it comes to power steering.

The only thing I can suggest is a visit to Lexus.

I did find this video regarding a poor connector on the rack which may be worth checking out.

Also this

 

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4 hours ago, steve2006 said:

Colin is the man for this problem, his hybrid knowledge is second to none. I’m old skool hydraulics when it comes to power steering.

The only thing I can suggest is a visit to Lexus.

I did find this video regarding a poor connector on the rack which may be worth checking out.

Also this

 


thanks for your reply Steve, who is Colin however? I’m relatively new here, (around 6 months).
 

so I just took the under tray off, all the plugs are plugged in and firm.

 

Searching on the internet for the eps ecu location, anyone have any idea? 
 

Thank you 

 

James

 

 

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Colin Barber another moderator on the club.

Look like the ECU is mounted on the inner wing area passenger side. From what I have read the rack looks a more likely cause though.

6B67FA23-1035-4E39-872F-0213A9F19773.png

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13 minutes ago, steve2006 said:

Colin Barber another moderator on the club.

Look like the ECU is mounted on the inner wing area passenger side. From what I have read the rack looks a more likely cause though.

6B67FA23-1035-4E39-872F-0213A9F19773.png

Thank you!

 

I think it’s a little strange that I can read the eps module when the error isn’t on the dash And steering is light but soon as it goes heavy and the warning comes up I can no longer read the module. Not sure how a fault rack would cause the inability to communicate with the module when fault exists.

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That fact struck me too as a bit odd, maybe worth paying Lexus to perform a code read?

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Little update, So I’ve bought a working eps ecu, a new Lexus agm Battery as the Battery is non agm in the car, plan to try them out over next couple days when they come, fingers crossed.

Im trying to avoid going to Lexus until the last resort mainly due to stealer costs. 

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Agreed on Stealership being the last resort! £££££££'s 

For what it's worth my daughters Fiat 500 was throwing up a "Have Power Steering System Checked" it is also an Electric assist system and the warning only came up after the car had not been used for a while ( it always started on the button and everything else was fine) and it never came up when the car was being used, but reading that EPS requires large amounts of electrical draw to function I got a new Battery ( smallest car Battery I have ever seen!) and have not had the fault show up since. So if you have any doubts about the state  or suitability of your Battery then that is a good starting point!

If the construction of the IS 300 is anywhere similar to the IS 250 then FYI the EPS ECU on the 250 is located under the Battery compartment tray. Apparently the connecting plugs are in very tight! 

https://www.lexusownersclub.co.uk/forum/topic/123699-electrical-connectors-under-battery/

Note: diagrams in thread are from a LHD car and Battery is shown on 'wrong' side!

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Update!

so the Battery didn’t do much, I’ll probably keep it tho as it’s the right one, after lots of swear words and telling the car to find another owner I managed to swap the ecu out, which isn’t in the boot in the mk3 it’s actually under the hybrid system in the engine bay, and no I didn’t enjoy working around that! 
 

I’ve swapped it out and the fault went out instantly, ill have to learn how to calibrate it to my car I guess, but proof will be in the drive later today and see how she goes

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I took a picture of the location incase anyone searches in the future and finds this post as I looked all over the place for it, in the wheel arch, under the car, everywhere as I couldnt believe it was burried under there hidden away!

lexuseps.jpg

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Hi All,

I thought I'd let you know that since replacing the EPS ECU the fault hasn't come back once 🙂

 

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2 hours ago, JamesRowe said:

Hi All,

I thought I'd let you know that since replacing the EPS ECU the fault hasn't come back once 🙂

 

Great news James! How much would that job have cost at Lexus do you think? And how much did it cost you?

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Sounds  like a good result - did you have to calibrate it and if so what procedure does that involve ? 

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I haven’t calibrated it yet, it’s from a used car (cost £40 which I think is a result), so it will be calibrated to a car. It actually feels perfectly fine to drive, so I’ve yet to look into the process but I know you do it through techstream

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22 hours ago, matt8 said:

Great news James! How much would that job have cost at Lexus do you think? And how much did it cost you?

Hi Matt,

 

Well I phoned Lexus and the diagnostic is £186+ vat at sidcup, plus the ecu which i guess would be over £600, then 2-3 hours labour, so were well over a grand, probably near £1500. - Its cost me £40 for the used ecu 🙂

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Good result, someone did you a favour at £40.00 was it a private breaker? I remember buying a used engine ECU for mine a few years ago as a spare for £20.00 you can almost add another zero on them now!

However when it comes to awkward jobs nothing beats the LS starter motor position...between the V under the intake!

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