Rx400h low engine oil warning

[welland]

This weekend, my 2006 rx400h began to give intermittent warnings about low engine oil level. 

Yesterday, the warning was displayed for a few seconds after starting the car and it went away by itself.  Then there were several trips when the warning was not displayed.   Today, the warning was displayed at the start of one trip, and did not go away until i stopped and restarted the car.  Then there were several trips when no warning was displayed.  

I have checked the dipstick and it shows the level to be about half way between Min and Max.  

So, is the electronic level sensor correctly warning of low level? In other words,  if I top up the oil, will the warning stop?

Or, is there a fault that's causing the warning to display when it shouldn't.  

Any thoughts?

[PCM]

No harm in toping it up a bit?

[royoftherovers]

2 minutes ago, PCM said:

No harm in toping it up a bit?

Spot on Piers.That is the first logical step he should have taken.

[PCM]

Oil changed recently, or not for a long time?

[welland]

13 hours ago, royoftherovers said:

Spot on Piers.That is the first logical step he should have taken.

Not necessarily logical to add more oil.  According to the dipstick it is not low.  

[welland]

12 hours ago, PCM said:

Oil changed recently, or not for a long time?

Last changed in 2019, but not done many miles this year, for obvious reasons.  Oil still looks clean and golden in colour,  same as it did when new.  

How is the age of the oil relevant to the level?

[royoftherovers]

10 minutes ago, welland said:

Not necessarily logical to add more oil.  According to the dipstick it is not low.  

Depends on one`s perspective Peter.

I gave an answer from my perspective, I was not criticising you Peter.

[The-Acre]

On 12/6/2020 at 11:55 PM, welland said:

This weekend, my 2006 rx400h began to give intermittent warnings about low engine oil level. 

Yesterday, the warning was displayed for a few seconds after starting the car and it went away by itself.  Then there were several trips when the warning was not displayed.   Today, the warning was displayed at the start of one trip, and did not go away until i stopped and restarted the car.  Then there were several trips when no warning was displayed.  

I have checked the dipstick and it shows the level to be about half way between Min and Max.  

So, is the electronic level sensor correctly warning of low level? In other words,  if I top up the oil, will the warning stop?

Or, is there a fault that's causing the warning to display when it shouldn't.  

Any thoughts?

Unlikely topping up the oil would make a difference if it's between the levels.  I'd consider the oil pressure switch to be suspect. It could also be the oil pump failing.

[welland]

Thought I'd give you a long-overdue update.  

A few days after my original post, I was driving along and there was no warning about low oil level, until I descended a steepish hill, whereupon the low oil level warning illuminated again.  I realised that there is a possibility that the oil level might be fine on level ground, but that it might give a low reading on a gradient, so decided to top up the oil after all.  

After topping up the oil, the warning has not been displayed again for a couple of months, so I think that was the problem.  

[m4rkw]

If the car isn't level when you check the dipstick you'll get an inaccurate reading.

[mr_s81]

Bit of a thread bump here, but I am having the exact same symptoms on my 2005 RX400h with 141000 miles. I changed the oil about 2 months ago and there were no issues until this past week. The car doesn't is only used 2 or 3 times a week presently as I'm currently WFH.

I have changed the oil pressure sensor but it appears to have made no difference. The oil level is at the top mark on the dipstick when on level ground, so I'm reticent to add any more. I looked the handbook and it indicates that the oil level and oil pressure are two separate warning lights.

I notice there appears to be some sort of sensor bolted to the oil pan, but I couldn't find much evidence online of an oil level sensor on the RX400h. Can any shed on light on what this might be?

Barring the warning light, the car is running very well as usual.

Thanks in anticipation.

[Herbie]

2 hours ago, mr_s81 said:

I notice there appears to be some sort of sensor bolted to the oil pan, but I couldn't find much evidence online of an oil level sensor on the RX400h.

Here it is:

[mr_s81]

@Herbieyou legend!

Guess I'll have to look for an oil level sensor instead. 

Thanks very much for the quick reply.

[Greisingel]

https://www.amayama.com/en/genuine-catalogs/epc/lexus-europe/rx400h/mhu38/5163/engine

I have bought parts relatively cheaply with reasonable delivery costs

And they have excellent detail along with VIN number drilldown

https://www.japan-parts.eu/lexus/gr/2005/rx400h/mhu38r-awxgkw/4_524210_002_309W/electrical/8401_switch-relay-computer#89491

[mr_s81]

On 5/12/2021 at 4:08 PM, Greisingel said:

https://www.amayama.com/en/genuine-catalogs/epc/lexus-europe/rx400h/mhu38/5163/engine

I have bought parts relatively cheaply with reasonable delivery costs

And they have excellent detail along with VIN number drilldown

https://www.japan-parts.eu/lexus/gr/2005/rx400h/mhu38r-awxgkw/4_524210_002_309W/electrical/8401_switch-relay-computer#89491

Apologies @Greisingel, I wasn't notified of your reply at the time Thanks very much for the info. I've been able to get the relevant part number and have hopefully sourced a reasonably priced replacement! 🙂

[ArturMucha]

On 7/19/2021 at 2:28 PM, mr_s81 said:

Apologies @Greisingel, I wasn't notified of your reply at the time Thanks very much for the info. I've been able to get the relevant part number and have hopefully sourced a reasonably priced replacement! 🙂

Hi man 

I'm having the same problem  just wondering if you sort it out with your lexus? 

[ArturMucha]

Have any one sort it out this problem? 

[Malc]

the checking of the oil level at cold or warm or when hot  could make a difference  ..........as does the going down hill activity too  ......... but assuming you're needing to sort out the greater isssues arising with your specifics then .........

........... there's of course the option to mail directly to either or both of these two last posters just in case they aren't visiting this post to respond 

Hope you get your mind settled soon on all this

Best wishes

Malc

[ArturMucha]

1 hour ago, Malc said:

the checking of the oil level at cold or warm or when hot  could make a difference  ..........as does the going down hill activity too  ......... but assuming you're needing to sort out the greater isssues arising with your specifics then .........

........... there's of course the option to mail directly to either or both of these two last posters just in case they aren't visiting this post to respond 

Hope you get your mind settled soon on all this

Best wishes

Malc

Thanks for advice I did now contact one of them because I'm limited to one message per day unfortunately 

[mr_s81]

On 5/16/2022 at 12:12 PM, ArturMucha said:

Hi man 

I'm having the same problem  just wondering if you sort it out with your lexus? 

Hi.

Yes, I got the problem sorted. I replaced the oil level sensor and the problem was rectified. It hasn't come back since. It's easy to change too, so could be done DIY if you so wished.

Thanks,

Ian

[Micho]

Hi guys,  i have lexus 2006 RH 400H. Its a nice car,  i also saw a low engine oil message and sound on the dashboard. When I wanted to start moving today,  I was terrified. I got to where I was going without issue and back home and wait for it to be cool, then checked the engine oil gauge. It just past the top line on the lower line. It shows the oil reduced. I have top it up. Please what can I do if it repeat itself. 

[ColinBarber]

30 minutes ago, Micho said:

I have top it up. Please what can I do if it repeat itself. 

Keep an eye on the level - check it weekly to see if it is going down. If the warning light comes on and the actual level isn't low then you may need to change the sensor.