2000 Rav4 1Az-Fe O2 Lambda Sensor Bank Identification

[Joylove]

Confirming a couple of posts on Autozone and Lambdapower that state Bank 1 is on the left of the engine, the Toyota documents state bank 1 is on the right as you look at the engine. Confusion may arise as "left" and "right" are different if you are sitting in the driver's seat or looking at the engine.

The Toyota part numbers

89467B Top SENSOR, AIR FUEL RATIO

89467-42010 LH 1 € 259.61 therefore Bank 1

89467-42020 RH 1 € 248.13 therefore Bank 2

89465 Bottom SENSOR, OXYGEN

89465-42090 LH 1 € 233.02 therefore Bank 1

89465-42100 RH 1 € 233.02 therefore Bank 2

And the Denso equivalents

DENSO OEM

Engine: L4 (2.0L) ID: 1AZFE

234-9023 DENSO is the O.E. Manufacturer / Air Fuel Ratio Sensor 1 Upstream Left OE Style GAS (FI)

234-9028 DENSO is the O.E. Manufacturer / Air Fuel Ratio Sensor 1 Upstream Right OE Style GAS (FI)

Engine: L4 (2.0L) ID: 1AZFE

234-4048 DENSO is the O.E. Manufacturer 1 Downstream Left OE Style GAS (FI)

234-4209 DENSO is the O.E. Manufacturer 1 Downstream Left Universal GAS (FI)

234-4048 DENSO is the O.E. Manufacturer 1 Downstream Right OE Style GAS (FI)

234-4209 DENSO is the O.E. Manufacturer 1 Downstream Right Universal GAS (FI)

The O2 sensors have 4 wires, two coloured wires for the sensor, two black ones that connect to a simple heater coil.

The heater coil is there to provide a qucik burst of heat to the sensor to meeet the EU emissions and are useless the moment the car leaves the EU testhouse.

However if the heater coil breaks due to the extreme conditions it is subjected to, then the ECU detects this break, and stores a fault and lights the EML (engine management light) (post 2002 cars only).

Moreover it then ignores the O2 sensor data and runs rich as a precaution, dropping your MPG and eventually damaging the cats.

If you think you may have a faulty sensor, use your multimeter to measure the resistance between the two black wires on each sensor. For genuine sensors, expect about 4 Ohms for Bank 1 and about 15 Ohms for bank 2. Open Circuit = failed heater and the car won't go closed loop.

Open loop fuelling will see your MPG drop to about 23MPG, the engine will be less "zingy" and eventually damage may occur to the Cats. Also you may experience trouble idling, with the car almost stalling as you draw up to a junction, especially if more than one sensor heater has failed.

Removing the vehicle Battery for several minutes will not clear your stored fault codes; but it will clear the engine adaptations. These will take 80-100 miles to recover. Expect lumpy idle when warm and less "zingy" performance during this period.

I recommend World Car Parts and eBay for sensors, depending on how many you need. eBay you can often buy all 4 for a discount. When removing your old sensors, don't cut away the cable ties instead release them from the back with pliers, the replacement sensors may not have the cable ties fitted. The DENSO sensors come with a sachet of anti-seize paste in the box, so you don't need to buy copper slip grease. A proper O2 sensor socket (about £6 on eBay) and plenty of plusgas (About £4 at Amazon or Halfords) left to soak with a healthy dose over a couple of days and applications is strongly recommended.

Some have reported the sensor resistance are fine, and that the GND path for the heater circuit can corrode. You may want to check that with your multimeter also if you find yourself at a dead end.

HTH

[pmb]

Been covered a few times on here with pics , may be worth you doing a search. As you look in the engine bay B1 is the RHS one but if you are sat in the car then B1 is on the LHS. Is that yes or no?

[Joylove]

Been covered a few times on here with pics , may be worth you doing a search. As you look in the engine bay B1 is the RHS one but if you are sat in the car then B1 is on the LHS. Is that yes or no?

That would be a yes. I searched, didn't find anything better than your post with the linked Toyota PDF. I googled even, didn't find any good pictures.

[anchorman]

No point doing a poll as there is only one correct answer.

Its quite simple. Bank one is always No1 cylinder and always at the front of the engine. The front of the engine is the pulley end which in your case is the drivers side. However, if you look at the top diagram you will see that the manifold twists over to the opposite side so remains bank 1 even though it is away from No1 cylinder. The reason is to make sure the cats (the big cylinders) are fed with even amounts of exhaust and by linking it to No4 you get one piston on exhaust and one on compression. When you turn the engine 180 degrees you get the same with No2 and 3 cylinders. The firing order is 1,3,4,2 and unless you did it that way you would get large sureges and large gaps which the cats have to process. This clip shows how the cylinders work in pairs;

Now with regard to that left and right thing, those always apply when sitting in the drivers seat. For that reason your car is a right hand drive.

Your photo is labelled correctly and as daft as it sounds, like your steering wheel the dipstick is on the RH side of the car

[Julianne Kardine]

Really grateful guys. Although its safe to drive at the moment I know i'm pushing it so now I can go shopping for a new one. Cheers Truley appreciated.

[anchorman]

Pardon?

[BigMo82]

This has been a helpful post for me. I have an Avensis with 1az-fse and have had a fault code P0057 which is bank 2 sensor 2. I changed the sensor yesterday for a new Denso and the fault code came back within a few miles. Having looked at your diagram I believe I have changed bank 2 sensor 2.

The sensor I removed from bank 2 sensor 1 is intact working which I have checked with a ohm meter. Would it be ok to cut the wires and just put reconnect this to the faulty sensor loom or are upstream and downstream sensors different?

Mo

[anchorman]

Different I'm afraid. They have different parameters before and after the cat.

[BigMo82]

Appreciate your reply Anchorman.

Mo

[BigMo82]

Ordering a sensor from Eurocarparts and they have them listed as right side and left side. I need to replace bank 2 sensor 2. Any idea if I need the right or the left sensor?

Mo

[anchorman]

Look how the manifold is twisted;

4.3 oxygen sensor location.pdf

You are looking at the 1AZ-FE engine.

[shaunrav4]

So if the downstream or sensor 2 goes then there is no rush to replace them as they are only used to judge the efficiency of the cat?

They are not used to calculate the fuel mix (only upstream ones are used for this)?

[gjnorthall]

The OBD standard requires a downstream Lambda in order to check the operation of the catalytic converter. On some cars the downstream Lambda is part of a closed loop control system and used to fine tune - not sure if this is the case on the RAV - in any event the effect would be minor. I wouldn't see a problem with driving with a faulty downstream unit - this would however illuminate the MIL and cause problems at the MOT (but strictly speaking - shouldn't result in a fail).

[shaunrav4]

Cheers for that , I've decided to change it anyway as the light was annoying me driving along. At least I'll know in future if something else trips the light.

To get the sensor out are these spanners any better than the socket with a slot for the wire.

http://www.ebay.co.uk/itm/US-PRO-3-8-Dr-22mm-Oxygen-Lambda-Sensor-Flexible-Sensor-Socket-Wrench-Spanner-/281152385072?pt=LH_DefaultDomain_3&hash=item4175fcf030

It looks pretty tight down at bank2 sensor 2 to get the extra long sockets on.

[gjnorthall]

Looks a good tool. The old sensor can be incredibly tight and is best done with the manifold hot - but take care. In case the spanner slips - use a piece of hardboard over anything vulnerable. Don't use release / penetrating oil containing silicon - the slightest trace will destroy the new Lambda.

[Slash Pants]

Hi All new this site and saw your string and wonder if you can help as my issue is similar.

I have a 2002 2.0cc Auto Rav4 vx

had EMS light on for some time as new O2 sensors were iffy but no issues with performance, got around 28mpg with very easy driving.

i thought this was Ok and probably improve when I eventually got around to changing sensors.

anyway MOT ran out and when put in it failed on emissions.

Garage said it was Lambdas so asked them to sort it. they changed B1S1 and B2S1 that sorted the emissions and past MOT but EMS light was still on.

They told me to do the other 2 would cost another 300 quid so thought i would do some other time as already past MOT.

But economy went down to 21mpg - Does this make sense to anyone?

Upon further investigation i am not sure the sensors they installed are right.

B1S1 - denso part no. DOX-0242 <> This I think is right from the data I have read

B2S1 - denso part no. DOX-0246 <> this I think is wrong and should be DOX-0277

can anyone confirm this and if they think its why i get stupid economy, so I can take it back

I must say these part numbers are confusing as there are so many.

Any help would be appreciated as I still need to sort the last two.

can any one confirm if they recon my MPG will go back up.

Thanks

[shaunrav4]

DOX - 0246 is right for sensor 1 bank2 according to spark plugs site

http://www.spark-plugs.co.uk/index.php/products/details/DOX-0246/830

matches toyota part 8946742020 according to that site which matches the numbers at start of this post

looks like both are right looking at them

the fact the light stayed on after replacing them would make me think there's another issue, especially as your getting poor mpg now.

Seems strange the garage told you to do other 2 after replacing those 2 , would be odd for all 4 to go at once, didnt they check the error codes and see what ones had actually failed if any?.

Was it a toyota garage?

I think you need to get it hooked upto a computer and see whats really going on?

Where in essex are you ? Perhaps someone has an Obd lead and software they could test the codes and values from your sensors.

Im in surrey so a bit too far i would think...

[Slash Pants]

Hi Shaun, sorry for late reply, I have been away in my gas guzzling Rav4 !

Thanks for confirming the sensors were correct that the garaged replaced, I must admit I got well confused as used another site for reference that said the opposite, will try a dig out the link but the spark plug site seems a good reference.

The garage I used was a independent setup and well respected from what I hear.

I did contact them and they did offer to check them out without any hesitation, maybe they can run a check again for me.

From what i read if the fuel sensors are faulty the management system defaults to a backup setting so if the management sensors are now good and the O2s are shot, that maybe the reason for bad consumption.

Just seems weird as you would expect poor MPG is kind of related to running rich hence probable bad emissions. But they needed to do that to pass the MOT.

Somethings not right, I will contact the garage to run a check again to confirm if the other 2 sensors are shot.

I am in Brentwood, Essex, so quite a hike from you, but thanks all the same.