Yes. To get warning light off. The code says octane not high enough. I use premium only. I saving my receipts from now on to show them. I think I got a lemon. We will see if it does it a 3rd time...

 

Yes. To get warning light off. The code says octane not high enough. I use premium only. I saving my receipts from now on to show them. I think I got a lemon. We will see if it does it a 3rd time...

 

What code did it throw? There's probably half a dozen code for low octane or something related to it. It could be a sensor malfunction, a bad cat, an incomplete burn, a misfire, etc.

 

A receipt shows proof that you PAID for high octane. It doesn't guarantee that you're pumping high octane gas from the storage tank. It could be diluted with water or maybe someone filled the storage tank with the incorrect fuel grade.

 

 

P137800 is not a low octane code. It clearly states that the air/fuel mixture is igniting too early in the stroke. Yes, you could be putting premium but you don't know if it's a bad batch. It doesn't matter if you have gone to the same station for the past 5 yrs. There's a chance that it could be a bad batch of premium fuel. Go to a different station for the next month and see if it comes back.

 

I have. It first did it at 3700 miles. I switched stations and it came back at 4700 miles, 6 weeks later...

oh well, let's hope that is it. I still got a little over 2 years left on the lease for this damn car.

 

It's still under warranty. So instead of having them clear the code like you want them to, take it back and don't get it back until they figure it out. They'll probably flush the tank, replace the knock sensor, put some good premium fuel and have you use a different station going forward.

 

yeah. It's probably a lemon...

 

i don't think that's what he was implying at all.

 

 

What Does the ‘Reduced Engine Power’ Warning Light Mean?

Modern vehicles which use this feature are pre-programmed to limit the performance of the vehicle to prevent further damage. When specific faults are detected electronically, the engine control module begins the process of limiting vehicle speed, gear range, and engine power. This can be caused by engine trouble, transmission faults, or even a bad battery.

Driving with the reduced power light or message displayed is possible, but this feature is called ‘Limp Home’, which is as much as the vehicle should be driven (within reason). There is not much risk of driving in this mode, since the vehicle will not be a pleasure to drive, acceleration will be poor, gas mileage excessive on some vehicles, and shifting gears is jerky at best.

In addition, some vehicles may disable the radio, or other non-essential accessory components. The short answer, it is best to tow the vehicle if it must travel further than a few miles. In general, it is not a good idea to operate a vehicle in limp mode, due to the overwhelming possibility of becoming stranded.

I've done a lot of research , this Reduced Engine power and Radio cut off happened on 3rd gen Lexus lately, the Transmission and shifting on Lexus had problems with 2nd and 3rd Gen Lexus IS/ GS so far. Dealer won't tell you the true but ill tell you what, when ECU set a drivetrain to limb mode is always something wrong with the Transmission electrical , my old Acura TL was samething , they reduces power and limits the speed to keep Engine/Trans from breaking down. You can do your own research and you'll see.

 

 

I don't believe its the tranny either, but the research said possible Tranny, Electrical or Alternator/Battery, this happens a lot on 200T RWD 350 8 speed Tranny

 

On knocking, per owners manual,

Lexus says 91 octane is required for optimum performance, but in instances, 87 may be used but cautions 87 may result in knocking and reduced performance. Lexus says occasional light knocking for a short time is ok during acceleration or going uphill and that this is normal and there's no need for concern. IIRC, in the US, cars should have the ability to run on 87 octane. So I dunno. I know this thread is old but I wonder if these people were accelerating hard for that message to come up. If that message came up during a low load scenario, I'd suspect a faulty knock sensor or something. or maybe some improperly gapped plugs