jbgunn

02 rx300 VSC & CEL lights are on and stay on, oil is 1500mi old and vacuum lines are all secure, brake res was low at last oil change, mech said i could have leak somewhere, would that cause this, i have not gotten around to code scanner yet

carguy07

Low brake fluid will not turn on the CEL. Your mechanic suspects that you have a leak and let you drive it away?

jbgunn

This was a mech at a lube center, I fiquered he was trying to upsale, I added some fluid when i got home and has been fine since, just curious i f this would cause VSC & CEL lights to go off, this has happened b4 during oil chane and mech pulled vacuum line apart(common) but this time no matter how mant times i reset the lights come back in day or 2

greg569

If its not a hose loose, then its probably code 1135 or 1155. Those are your flow sensors in banks 1 and 2. It will cause both VSC and CEL to go on.
I have read many posts about replacing with denso parts sold on amazon. I tried this last week with 1135 bank 1 sensor 1. Now Im getting 1155 bank 2 sensor 1 code with CEL and VSC light still on.
A mechanic suggested I replace the denso part with a factory lexus part and see if it fixes the problem. Im suggesting buying a second denso flow sensor and putting it in bank 2, the one in front by the radiatior,, code 1155.
Could anyone take there best guess and tell me if Denso has parts that will not throw codes, or in this case do I need to stick with the $220each parts from lexus.
Thanks

carguy07

The Denso part is an OE part, not an OE equivalent, it is the exact same part made by the same manufacturer. Just 2 part numbers so Lexus can mark their part number up 100%. The Denso part on amazon will not throw codes, it works perfect.

greg569

thanks carguy-
I thought I might have 2 bad sensors. I have been driving for a year with the CEL on and I dont think my old 1155 sensor could handle the new 1135 sensor. I have read that one can draw on the other if shot. However, im getting the right ohm reading from bank 2 sensor 1.
I will let you know how it turns out.

code58

Greg, Carguy gave the the straight answer. The Amazon Denso sensors are the EXACT sensor, just lazer etched with the Denso# instead of the T/L#. Even though Denso makes the sensor for T/L, they can't sell it with the T/L# on it without paying T/L for the privilege because that # BELONGS to T/L.
As you know, both the 1135 & 1155 #'s are heater #'s. It is very possible that your sensor heaters both went out that close together (that's the most common failure on the sensors), but it's easy to see if they're bad if you have a DVM or continuity tester. Just check continuity on the 2 black wires. No continuity, bad sensor heater, continuity, good sensor heater, it's that simple. The heater failure won't affect running hardly at all and won't really hurt anything if run that way, as you've found out. The other part of the sensor (actual sensor part) is a different story. I seriously doubt that the new sensor even knows the old one exists.

P.S. I do trust you got the CORRECT sensor from Amazon, not the sensor behind the Cat. Conv., which IS an 2 sensor, not an A/F ratio sensor.

greg569

Code58-
I think I got the right sensor, denso part 234-9009. Checked with Denso as well.
I did run a continuity on the bank 1 sensor 1 and it had none. But I just ran on bank 2 sensor 1, code 1155 and It does have continuity? Ordered another 234-9009 from Amazon.
Keeping my fingers crossed because $87.53 per sensor is getting costly.
Only other thing im thinking is maybe a/f relay? Will replace engine before dealer takes my money.

hypervish

I'm a little lost.

What code do you have currently?

Which sensors have you replaced already?

greg569

I Had code 1135. Replaced Bank 1 Sensor 1 with Denso part #234-9009. I cleared the codes and code 1155 came on. Going to try and replace sensor 1 bank 2 with Denso part #234-9009. Currently have code 1155.

code58

Greg, that DTC is specific to the heater in the front A/F ratio sensor. (B2S1) If you have continuity on the 2 black wires, the heater is probably OK. Did you check the Ohms on the front A/F sensor? I have cut them apart with a die grinder and a thin blade and the heater is a pretty simple thing, and it was clearly evident that the heater was broken. I suppose it's possible the heater element could touch enough to have continuity but be broken and show a code but it should have pretty high Ohms if so. The heater is such a simple thing I don't think an old one and a new one together would make any difference as long as it wasn't broken. Yes, as you know, the # you listed is correct. You are very fortunate with the price. When I replaced them on my DIL's RX, the BEST price I could get online from a Lexus dealer (discounted) was $150. I asked the local Toyota dealer if they could match the price on 2 of them because I needed them right away. He said no, but he did give them to me for $162. ea. At that time the Lexus dealer got about $250. ea.

greg569

They really get you with these prices. I can't imagine it costing that much to make one.
With code 1155 im going to try and replace B2S1 a/f sensor, and hope for the best. I did check the ohms across the black wires of the front sensor and do have continuity. I get the part on Friday.
Completely lost if this dosent work.

greg569

So far so good! Replaced both sensors and reset codes. No engine light yet!. Front A/F sensor, bank 2, takes 5 minutes with a 22 mm box wrench and a little elbow grease.
Almost thinking of replacing o2 sensor behind cat to complete but going to leave well enough alone. Thanks for everybodys help.
Amazon Denso parts and club lexus. Saved me about $800!

greg569

Just passes smog with almost zero emissions. Anyone living in Ca would know what a great thing that is. Also shows car is running perfect!

insuralife

Would this defective part also cause a very low idle and stall-out condition. intermittent problem.. only at intial start up. After operational for a while the low idle is gone. lights always remain on..
thanks in advance...