Help Check Engine Light + Trac Off Light (Knock Sensor)

[sexy lexy 99]

Hi,I have a 99 ES300 the check engine light and trac off light came on simultaneously a few days ago. I pulled code p0330 (knock sensor)I understand the sensors and the labor is expensive,I don't get why when the lights come on I loose overdrive. I don't wanna throw $ into it if it is transmission problems. Do theese cars go into some kind of fail safe mode ? What is the plan of action to fix this problem? Any helpful info is much appreciated! : ) The lights do come off and back on (every few hrs) When there off overdrive is restored,when there on SOMETIMES I still have overdrive. Please help me figure this 1 out Thanx!

[lenore]

If that is the only code, yes you have a bad knock sensor...The part is not bad price wise, but you have to remove the intake manifold to get to the knocks sensors. Highly suggest having the coolent hose under the manifold replaced at the same time...I did this job my self, and it was not fun. Took about 5 hours with most of the time spent fighting hidden bolts between the firewall and intake manifold. You should replace the intake gaskets while doing this job. In the RX300 forum stickys there is a writeup on how to do this.

[sexy lexy 99]

Thank you for ur reply lenore! Just seen ur currently located in Roseville. Me too haha ! I will look for that post about the rx300. (is that the same engine ?)Was wondering if u could tell me anything about the trac light and the no overdrive issue

[lenore]

Thank you for ur reply lenore! Just seen ur currently located in Roseville. Me too haha ! I will look for that post about the rx300. (is that the same engine ?)Was wondering if u could tell me anything about the trac light and the no overdrive issue

Those lights come on when you get an engine fault....Make sure there are no secondary codes....The engine goes into limp mode when the check engine light.

[lenore]

here is writeup from other Lexus site:

http://www.clublexus.com/forums/rx-first-generation/485531-rx300-knock-sensor-replacement-diy.html

[Lexlogic]

here is writeup from other Lexus site:

http://www.clublexus.com/forums/rx-first-generation/485531-rx300-knock-sensor-replacement-diy.html

Another write up I used here is the Link

[lexis lexus]

My understanding of this situation. When knock sensors fail to provide any signal (either due to bad sensor or more likely due to fried wiring harness which sits in the valley between the two heads on top of the block, perhaps the hottest place in the engine compartment aside from the exhaust manifolds), the engine defaults to a state to prevent knocking, this takes out overdrive and traction. Seems a design flaw to me, but then it generates a lot of $1500, visits to Lexus dealership...

LL

[chococat]

Hi,I have a 99 ES300 the check engine light and trac off light came on simultaneously a few days ago. I pulled code p0330 (knock sensor)I understand the sensors and the labor is expensive,I don't get why when the lights come on I loose overdrive. I don't wanna throw $ into it if it is transmission problems. Do theese cars go into some kind of fail safe mode ? What is the plan of action to fix this problem? Any helpful info is much appreciated! : ) The lights do come off and back on (every few hrs) When there off overdrive is restored,when there on SOMETIMES I still have overdrive. Please help me figure this 1 out Thanx!

Everyone has answered, but what you are experienceing is what I experienced. I have a 2000 and replaced my knock sensors in 2007, both of them actually. My original codes were (2) P0171 - system too lean & (1) P0330 Knock Sensor Bank 2 circuit, this was at 125,700 miles. We replaced both KNOCK sensors w/OEM Toyota #89615-12090 - $360 at 126,320 miles. At the time, I was married, but the job wasn't overly difficult. I think someone quoted 5 hours and that seems about right. And yes, it will mess with your overdrive as a built in safety mechanism. Bottom line...fix it, either dealership or yourself.

[Mayorchuck]

My wife's car has this exact issue. While reading up on the P0330 code, I found where someone had made a splice so that the module EC1(?) was reading the signal from the good knock sensor for both 1 and 2. Anyone done this? Just paid college tuition for two in my household so thought I would see if there was a cheaper fix, even if only temporary.

Thanks

[lexis lexus]

MayorC,

I recall reading that on the forum as well, and last year when I was getting knock sensor codes I tried it, as well as running a wire from a knock sensor mounted to one of the intake bolts by cyl #6 (driver's side, front bank). It was suggested that as long as there was competent signal coming from some knock sensor, the computer would act normal.

Well, the externally mounted knock sensor approach didn't work, I guess because there wasn't enough vibration/signal generation. The jump from the bank 2 knock sensor to bank 1 knock sensor didn't work either, but this was due to both sensors being toasted (literally) when I finally dug into the valley.

Overall, the jump at or near the connector below cyl #5 is definitely worth a try IMO. Takes about 20 mintues, and if it doesn't work, you haven't lost anything. It would also be worth a try to back probe the wires from that same connector to the computer, just to make sure there's continuity.

LL

[Mayorchuck]

Thanks LL. I can erase the codes and the lights stay off for about 15 minutes. OD works on and off after lights come back on. I have read where others have used fuel cleaner for several tanks to get rid of the problem. Anyway, you are saying the connection to the sensors are visible near cyl 5? How are the cylinders numbered? We have a 2000. I will dig around for that info. We have had this car for 7 years with absolutely no issues at all so this is the first time I have had to research anything for it. Thanks for your help.

Chuck

[lexis lexus]

Chuck,

First, I need to qualify my advice, as I'm most familiar with the 1mz fe engine from the '94-'97 mark. However on most toyota/lexus v6's, # 5 is the back driver's side.

The connector probably sits just below the valve cover adjacent to the end of the head, with wires running forward and diving into the valley below the intake manifold. To get a better look at it you may need to take the air filter lid and snorkel off the throttle body.

Fuel cleaner won't fix the knock sensor problem. When the cel is set, it's because there's no signal. It's either a knock sensor, the wiring harness, or problem going from the connector to the computer. If you're showing only one knock sensor code, then this is a good prognostic sign that the jump will work.

Try the jump, if that doesn't work, back probe the connection to the computer, and if you get that far w/out success, you'll need to take the whole intake off to replace the sensors.

Can get guidance on this from many of us if you have to take it apart.

Fun if you like to wrench, and a good way to save a lot of money.

LL