2016 Lexus RX350 40K miles (California Car)

P160500 Rough Idle / Engine Knock Sensor

Paid for 3rd Party pre-purchase-inspection. No active Check Engine Light (CEL) and car idled fine for 30 minutes. Car serviced at Lexus Dealer every 5K-10K miles, and no mention of this Code in service history. Any idea if I should be concerned? Why is this coming up in the scan?

 

If it's a one-time event, then it could be a tank of substandard fuel. So if a fresh tank of Top Tier quality fuel makes it go away, then that's not a serious concern. If it becomes a repetitive pattern, that is a concern and would need further diagnosis.

 

Thank you for the response. I have follow-on questions for “one-time event”: (1) What does this code signify? (2) Wouldn’t Dealer investigate and log during service? (3) Why would Dealer not clear this code, prior to putting it on market? I am trying to understand how common and how critical this code is. Unfortunately, the dealer I am buying from is not Lexus.

 

I have no knowledge beyond what it says -- "Rough Idle / Engine Knock Sensor". There's a sensor that picks up unusual vibration associated with the spark ignitions, and apparently logs a record if it exceeds a specified limit. So at some point the engine ran a little rough at low rpm. Don't know why, don't know why the log wasn't cleared. Won't matter if it doesn't happen again. I've had two Lexi, and never saw or heard about this code on mine.

 

UBDumass - Our 2021 RX ran poorly on Costco regular, but idled ok. We put in a full tank of premium at Costco. The engine smoothed out beautifully. Dealer says that's normal, no engine computer tweaking required. I hope this helps.

 

Are you frequently jumping between regular and premium gas? Cars don't have a way to detect what octane gas is in the tank, a knock event has to occur for the ECU to learn the gas is lower octane than before and then it will pull timing.

 

Quote:

Originally Posted by UBDumass

2016 Lexus RX350 40K miles (California Car)

P160500 Rough Idle / Engine Knock Sensor

Paid for 3rd Party pre-purchase-inspection. No active Check Engine Light (CEL) and car idled fine for 30 minutes. Car serviced at Lexus Dealer every 5K-10K miles, and no mention of this Code in service history. Any idea if I should be concerned? Why is this coming up in the scan?

I found this info on a Avalon link with your code. http://www.tavalon.net/1695/rough_idling_p160500_.html
That link lists things that would throw a 160500 code on Toyotas.
For a more reliable answers take it to Lexus Service, and have them to run an diagnostic.
Hopefully, you just had some bad gas, and need a tank of premium run through it.
2cents....

 

Thanks for everyone’s feedback. We picked up the car on Saturday, and made a long drive from LA to SF on Sunday. Everything is working as designed, and no Check Engine Light so far.

 

Posting an update... No problem driving 350 miles from LA to Bay Area, and trouble-free for past 3 weeks. Except last night and this afternoon, car would inexplicably rough idle. Scenario: (1) Drive 30 minutes, (2) Park 15 minutes - Though I don't think duration matters, (3) Start up and change gear to Reverse, (4) Car revs up/down/up/down aggressively by itself (As if car is gasping for air), (5) Put back to Park and car settles, (6) Change gear to Reverse and drive, as if nothing happened.

I should add, there is slow oil drip/seep, which I suspect to be Timing Chain Cover Gasket (From all the research on this forum - Big thanks). I don't think the two events are related, but curious how quickly I need to schedule an appointment. My Powertrain warranty expires in Dec'21.

Anyone familiar with the seriousness of this problem? There is no CEL. Would Lexus Tech be able to pull history or replicate the problem?

 

This is totally reminiscent of a scenario that happened when cars used carburetors to mix the air and gasoline. It has to do with the fact that the engine cooled down partially after it was shut off. So you have an engine that is not cold, but not fully warm either. It needs an intermediate fuel/air mixture that is slightly richer than what it needs when fully warm. I would first suspect the fuel injection system -- the dealer may be able to detect a calibration issue or other needed adjustment. Basically it is running too lean -- it is gasping for more gas, not more air.

 

Thanks for the response. I understand the logic, but why would it disappear after turning off/on the engine? Does the sequence reset and computer no longer recognizes this problem?

I would like to hear if others have seen erratic idling on a 4th Gen RX. I can’t be the only one.

 

Hello looking for some advice for my 2016 Rx 350......
The front left strut is banging when I go over bumps or dips in the road. I took it into Canadian Tire first to see what they would quote me for repair. I already knew that it was a front strut or shock issue as I had the same thing happen when I owned a 2008 Highlander. They told me that the strut is leaking and that for the year of the car it should not be failing. I have an appointment on Friday with Lexus to see what they say. The mechanic at Canadian Tire believes this should be a warranty issue since struts should not be failing like this only 5 years into the cars life. I have only owned the care for 1.5 years, and the past year due to covid the car has to been driving much.
I was told both struts would have to be replaced even though the right side is perfectly fine. I have read that you can replace only the fault strut without having to do both sides IF the other side is in good working condition. I would really appreciate some advice and maybe some tips on what I should say to Lexus so I don't get the run around and screwed out of thousands of dollars! Canadian Tire quoted me $2500 to have it fixed!!! I am praying that Lexus deems it a warranty issue due to the strut leaking, but since I am the second owner I am not too sure.
Thank!!

 

Shocks & Struts are consumable items and NOT covered by warranty.
WHY do you take any vehicle to Crappy Tire? Their mechanics are graduates of the Guesswork Technical Institute. (most of them) that mechanic you spoke with graduated from GTI "Summa *** Laude"
Yes the struts should be replaced in pairs for YOUR safety. They should run around $500 each including labour.
How many Kms on the vehicle, also you don't know what the previous owner did or did not do with that vehicle.
Listen to what the Lexus dealer says and if not acceptable look for a GOOD independent mechanic also to keep in mind is that any work done by a Lexus dealer comes with a warranty which I think is 1 yr or 20K Km it may even be 2 yrs and 40K Km check with them.

 

I agree with cocal
A reliable independent shop should be able to do this job easily. Struts wear out and you should change both fronts at the same time. The other is close to worn out too and the car will handle safely and smoothly with both being new. I don't know current Canadian pricing but believe that $1000 for both is reasonable. No reason to use Lexus struts when other popular brands are less money and work well on the RX. You can always do a search on this forum for more specific info. Also, in the future, you should start your own thread, this one is about another subject.

 

Thank you for the info, Lexus quoted me $776 all in to replace just the strut. The warranty on it was 4 years or 80,000kms.....the car is at 143,000 (high I know) The previous owner was an elder gentleman who took it down to Florida every winter.
Sorry about posting here, I am new to the forum game! I didn't think it would really matter or bother anyone who was genuinely interested in Lexus vehicles and offering advice on them. I promise to post elsewhere next time

Like my Lexus but LOVED my Toyota more !! Anyone want to buy a 2016 RX 350 ??!!! lol!!!