Pete44131

I have a 2000 ES 300. I am having an issue intermittently with a knock sensor code (bank 2).

Previously I started having bank 1 lean problems and then cleaned the MAF sensor, changed the air filter and all was good for a few weeks.

Then the other day driving with the AC engaged (winter time now but ac for defrost purposes), on the freeway, the engine light comes on and traction goes off. Also getting ABS light. I think when I first experienced the previous bank 1 lean problem was also triggered by running the car in hot weather, uphill, with ac on.

I've read that the knock sensor is a tough one the replace and am wondering if there are any other considerations to make before going that route of knock sensor swapping.

Thanks.

llcoolpass

how many miles on the original upstream 02 sensors?
" " spark plugs?
have you tried using premium [for your region]?

ASG14

iTrader: (1)

The knock sensor can br a trickey one. I've had to replace them on several different 1MZ's. It;s not a fun job.

Has the CEL gone on for the knock sensor more then once?

The ABS and CEL have should have nothing to do with eachother. The Traction Control light and CEL are intertwined, so thats normal.

IF in fact the knock sensor is bad, just 1 of them, you CAN go to the wires at the ECU, cut the knock sensor wires, and wire the 1 good one into both plugs in the ECU. I;ve done it, and many of my friends have (mostly guys with the TRD Supercharger). If you tackle the jon yourself, I can wa;lk you through it. You will need a couple other replacement parts as well.

llcoolpass

i thought the knock sensor was only an issue on the 1994 model. the solution was to relocate it.

you sure its safe to run on only one knock sensor? hopefully not running regular gas on that.

i would think the knock sensor doesn't go bad but is just so sensitive that the engine when aging knocks and the sensors hears it more than is practically needed.

what if the knock sensor code is for a legitimate reason?

ASG14

iTrader: (1)

No, all the 1MZ's have knock sensor issues. I know several people that have blown the knock sensor on a 1MZ simply with bad gas. I actually have a friend that blew one on his 3VZ with bad gas. I've blown 5 on my '96 Supercharged 1MZ. I've replaced knock sensors in 1 friends SCed '00 Camry, and another friends SCed '00 Solara. I;m not goign to say it's common, but it's not rare.

And yes, it is safe to run 1 knock sensor. I;m actually running 1 on the OUTSIDE of the engine, in the front. Made a crappy bracket for it. Several of my friends are currently, or have run only 1 knock sensor.

IF the knock sensor code is for a legit reason, it should mean the sensor is bad. Usually it will just retard the timing due to the knocking. If the CEL goes off for the knock sesnor, it;s usually the filiment inside the sensor that's bad, or goign bad. BUT, in many cases, (even myself), I've had the code, reset it, and all was fine. Sometimes it is a weird fluke. IF this was the 1st time it came on, see if it happenes again soon. If not, it should be fine.

97'ES

wow you have a lot of 1mz experience under your belt. the problem I have is I'm sure the engineers placed an acoustic sensor in a strategic location for a reason. one would most likely assume they have good reason in using two (each bank I would assume?). I've never replaced one just throwing in something that makes sense to me. One wouldn't think lexus was trying to waste money but who knows, overkill certainly happens.

ASG14

iTrader: (1)

^ If you want a laugh.

My friend has a SuperCharged 1MZ. He is running 1 knock sensor, bolted on a bracket to the toolant filler neck (for easy changing). For a couple years, he never blew one. We were always wondering IF it actually worked. We really didn't think it would save the engine if there was a need.

Well, long story story, he was street tuning, made a mistake, and yes, he actually blew the single relocated knock sensor and saved the engine. We were both quite surprised that day. Wasn't actually expecting it to work relocated there. But it did.

This is wher emy friends knk sensor is that I was talking about ^.

Pete44131

I have not changed the plugs in the two years I've had it or the O2 sensors. I do not use premium either.

Do you think plugs and wires could clear up whatever is triggering the knock sensor?

When I posted, it was the first occurrence of the knock sensor. then it happened again yesterday. only on the freeway.

Pete44131

it happened once when I posted and again yesterday... only at freeway speeds. that may be a coincidence or maybe the high speeds are where the knock presents itself. Freeway speeds of 70-80 probably

Pete44131

Not to sound stupid but what is the purpose of the knock sensor? Detect a knock and shut the engine down before you tear it to pieces?

GEORGE_JET

Knock sensors detect signs of detonition, and RETARD the timming, not shut the engine down.

Several posts ago, IIcoolpass asked about the spark plugs, and the mileage, also about what grade gas you are using. This is a very good question, but I do not see any reply to this.

I do like the idea of re-positioning the sensor, but I would suggest looking for a mounting spot on the block itself. By mounting it on the intake manifold, you may possibily attenuate the signal and reduce the sensitivity of the sensor.

Pete44131

I answered earlier that I have had the car for 2 years and not changed the plugs or o2 sensors and I run regular gas.

I think maybe plugs and wires may help the situation out. How about you?

GEORGE_JET

sorry, I missed your reply. 2 years is not that long, unless you put a lot of miles on the car. At this point, I think ASG14 has the best idea. Since the sensors are located so close together, I would suspect that significant pinging in one bank, would be picked up on the other. There may be slight risks involved, but I would not too concerned.