The report indicated that it failed due to failing the misfire monitor. No check engine light but I can not get plates unless fixed. Have an appointment at the dealer next week.
Anyone else have this problem?

 

Do you have your actual emissions test readings, like HC, NOX, etc.?

You might also just want to hop over to an AutoZone and see if you have some pending code in your system, i.e., OBD2 codes that read like P03XX or something like that.

 

No codes and they do not test exhaust gases-just checking to see if all of the monitors have run and passed. If there are one or more monitor that failed then it fails the test and I have to get it fixed to get plates renewed. The monitor (computer run internal test) was for misfires. Auto Zone can not look at the monitors-just checking for codes.

 

If this is an emissions-related failure, this should be covered by Lexus under the 8 year or 80K mile federal emissions warranty.

 

So very true- unless you have put one whale of a lot of miles on that '08, This is the dealers problem, not yours.

 

Took the RX400h to the dealer today and they confirmed that it fails the misfire monitor (mode$06). They think it is in the hybrid drive unit. They still have it after working on it all day.

 

I know it is sometimes difficult to get the exact details from the dealer when they perform warranty work, but since I believe this is the first time this particular problem has been posted on this board, I think many, including myself, would be very interested in knowing as much as possible about the failure, its causes, and the solution(s). Could you give us as much feedback as you can get? I have generally found this has to come from the service manager and not from the service writers.
Thanks for all you can provide.
Wyle

 

No word as to the cause. They are calling for help from corporate.

 

Update. DSM told dealer to replace the Goodyear tires (8500 miles) with Michelin as he thought that the cupping on the inside edges could be causing the misfire or at least the computer sensing that a misfire had occurred. I'll know tomorrow (Friday 9-19)

 

Either way you are much better without the Good (BAD) Year tires. More info by doing a tire search on the RX400h.

 

Interesting they think it could be tires. The misfire sensor looks for changes in crankshaft speed which can be caused by a cylinder misfire. I have heard of false signals caused by rough roads, but never tires. Is it possible that since the engine in the hybrid is hard connected to the drive wheels through gears, and doesn't have a fluid drive (torque converter) which could slightly dampen feedback from tires or the road to the engine, that the hybrid engine would be more sensitive to slight torque load changes caused by cupped tires? Just a thought for those who enjoy thinking about such things. You normal people just ignore it.

 

who who had thunk it

 

Update. Picked it up this morning and dealer said that no one can help and that they are out of ideas. Told me to contact corporate and open a case which I did. Their other Rx400h at the dealer do the same thing so it is not just my vehicle. Have another appointment for October 28 two days before my plates expire. I hope they can get it fixed or I am walking.

 

Hope this isn't a congenital problem with this hybrid that might show up as other symptoms. California and I assume most states do not require smog tests of hybrids, so there well might not be much of a track record for this test.

 

Isn't it all under warranty, so shouldn't they give you a loaner?

How many miles do you have?