This is my first post here, having lurked for awhile. I'm a 1-2 banana guy so I never have much to add, but thought this might be worth sharing since there's not much out there on it.

My '06 GS300 AWD has the CEL and VSC off lights on and is throwing a 51 code (bank 2 sensor 1 heater circuit malfunction). My gas cap is new, MAF and throttle body clean, etc. and because I was going to have to get down in there anyway, I decided to replace the sensor rather than just try and test it. I ordered a Bosch OEM fit A/F sensor from Amazon (part #15118) for $140 shipped. They also currently offer the Denso 234-9053 for $155 shipped. Those are the only two sensors that I could confirm will work for the right side on the AWD. Both are considerably cheaper there than anywhere else I found.

Anyway, part arrived today - here's the job...

Tools
1. #10 socket
2. Socket wrench (I used a standard size - wish I had a breaker bar)
3. Socket extensions
4. O2 sensor socket (a must for this job, imo)
5. Phillips head screwdriver

Steps
1. Remove passenger side plastic cover and engine cover
2. Disconnect and remove battery
3. Remove the plastic battery housing - the positive cable is clipped to it and must be popped off.
4. Remove 3 phillips head screws in plate on the power steering ECU underneath the battery
5. Remove #10 bolts and ground wire around the p/s ECU - there are 3 above it, one below and to the left (fender side) and one more underneath it
6. Disconnect the p/s ECU. It's connected on both sides - I only disconnected the engine side by releasing the white locking clip and it came off fairly easy
7. Remove the last #10 bolt in the plastic battery tray and remove the tray - now you have easy access to the sensor
8. Reach behind the engine and disconnect the sensor harness - it's a bit of a tricky spot and the clip is on the rear side of the harness. I loosened the clip with a screwdriver and it pulled off fairly easily
9. Using the sensor socket and extensions, loosen and remove the sensor. This was the most difficult part for me since I didn't have a breaker bar and that thing is really in there. I sprayed a little WD-40 on it and kept at it and it eventually broke free
10. Place a little anti-seize on the threads of the new sensor, being careful not to get it on the sensor (the Bosch came with anti-seize already on it)
11. Replace the sensor
12. Reconnect the harness, clip to the rear
13. Replace the battery tray and #10 bolts, making sure to reattach the ground wire
14. Reattach the harness to the p/s ECU and reclip
15. Replace plate, 3 screws and 2 #10 bolts
16. Replace battery and battery housing. Reclip positive cable and reconnect.
17. Replace engine covers

This is an easy job that will take <1 hour with the right tools (large wrench and sensor socket). It took me a little over an hour, with probably 20 minutes invested in trying to get the original sensor loose. I couldn't find any DIY for it, so hopefully this will help someone else.

Unfortunately, the P0051 came back a short time later so I'm going to have to take it into a shop and have it scanned anyway. But I've got 80k on it, so I'm not disappointed about the replacement and would have had to do the work anyway to test the old one. If anyone has any advice or troubleshooting suggestions for that code it would be much appreciated.

The first pic is where to look. The 2nd is the sensor itself, as seen with the battery out. The 3rd is the p/s ECU, showing the bolts, screws and harness. And the 4th is an 80k sensor next to a brand new one.

 

Excellent write up! Added to the FAQ / DIY section.

Thank you

 

Very good writeup. I have the same lights (VSC TRAC, VSC OFF, CEL) and code (P0051) on my 04 GX470. I am thinking doing the same fix. However, by reading all relative treads in the Lexus forum, I am not sure the code really means "the bank 2 sensor 1 heater circuit" or could be something else. Just wondering how you get the code reset after?
Thanks

 

I had the same code in my 2004 LS430. It is the passenger side O2 sensor closest to the front of the car...the one before the catalytic converter. Bank 2 refers to the passenger side. Sensor 1 refers to the upstream as I mentioned. Do it yourself and save tons of money. With the money you save, you can go to any auto parts store and buy a OBDII code reader/scanner that will cancel out the system. I bought my scanner at sears and it has the erase function that resets the on board computer.

 

I took mine in last year for complaints about the engine running rough and one of the things they found was some bad O2 sensor readings. There is apparently a TSB for that and they replaced them with a redesigned O2 sensor and a new ECU to account for the changed sensor design under warranty.

So, be careful about the parts you're ordering. You could potentially end up with O2 sensors that are reporting ranges of values that are out of spec according to the old ECU. This could very well be why the error codes returned even after you did the work. The ECU change to match the redesigned sensors is likely a huge cost, if this is the case and you have the wrong sensors hopefully there is still some way to find the sensors that were designed for the old ECU.

 

Thanks for all the helps.
Mine ended up with the bad heater in the Bank 2 Sen 1 O2 sensor. DIY replaced it with a Walker OE O2 sensor just before our Canada trip. Reset the code. Now it has been 7 days and 1000+ miles. Run great!

 

This just happened on my wifes 2004 gx470 check engine light came on as well as the vsc lights. From what i can read above everyone is pointing towards o2 sensors, am i correct. I reset the code after cleaning the intake, MAF sensor and also made sure gas cap was tight. i will give it a few days and go from there maybe it was the gas cap which i hope.

 

I have P0051 for my 2003 LS430, which side sensor it would be? How to check it? Also, I've heard to replace the senor, we have to remove the seats to connect the new sensor, is it correct? Thanks.

 

Hi all,

I am getting P2198 (Bank 2 Sensor 1) and the same VSC light. Do you think this still be an O2 sensor? because everyone talks about error P0051 for the O2 sensor! can some one please confirm which one I need to buy, I am looking for the OEM part number?
LH (89467-30010)
RH (89467-30020)

 

That refers to the sensor on the drivers side on the manifold. I believe this is the part: https://www.amazon.com/gp/product/B0...=ATVPDKIKX0DER

I too had the code. Have you had any symptoms with this code? I'm not certain my problem is the sensor.

 

The car runs perfect, the light doesn't stay on for long, maybe for 2-3 days stays on and it turns off for a week or two, the one thing I've noticed is when accelerating I would smell a rotten eggs smell and even passengers in my car would notice that smell too. I've bought a scanning software that reads live data and P2198 was the only error code present and voltage from the O2 sensor was zero!

some people are talking about a calibration that must be done at the dealership and its not necessary its a bad sensor. Any thoughts?

 

They're actually Air/Fuel sensors (Not o2) That code could be a few things, but if the voltage was reading zero, sounds like the sensor is bad to me. Luckily, its the easiest one to change. It's right on the drivers side manifold. You have to do a little reach around to get to the clip, unplug & unscrew.

I've read the TSB about the CPU reprogram and the Sensor upgrades. I'm not sure what actually warrants the change. I too am curious, what will happen if I just replace it with the same type as the bad one. I wish I could be of more assistance.

 

I thought Bank 2 Sensor 1 is on the passenger side not the driver side because in the first post he is talking about removing passenger side plastic cover and engine cover? so the oem one should be LH (89467-30010) if you are standing infront of the engine?

 

I think he had his mixed up. (which is why his code came back) The heated o2 sensors (Sensor 2) are underneath on the exhaust. The A/F sensors (Sensor 1) are under the hood. Bank 1 is the passengers side, Bank 2 is the drivers side. There are 4 sensors total. P2198 is Bank 2 (Drivers side) Sensor 1 (A/F sensor under the hood)

 

Thank you Hanxious for your confirmation, I would like to buy the OEM part, so based on my research I've found the two part numbers:
LH (89467-30010)
RH (89467-30020)

Now, will bank 2 sensor 1 is a left hand side or right hand side? when you say LF are standing infront of the engine or sitting in the driver seat?

Thanks again