Oxygen Sensor Replacement

[just355]

Can anyone give any advice on replacing oxygen sensor on 2003 Rav 4 vvti petrol

I am told by Main dealer bank 2 sensor has failed - as engine management light has come on

I need to know how you identify bank 2 - is it on left or right of engine bay etc

( there are 4 seperate sensor wires coming out of exhaust manifold in engine bay and all appear similar)

Dealer was useless when I previously tried to book it in and also wanted £3oo plus, for what I am told is a 10 minute job (with £150 part )

which is why I am attempting it myself

Any advice would be appreciated

Regards

Justin

[druand]

Read post following yours "Its been a while" you might just save a few pounds.

Best of luck with problem.

You will find there are a lot of good independent garages who have diagnostic equipment capable of checking most makes at much more reasonable prices. Bosch,Lucas, etc all supply sensors sometimes kess than 1/2 price of main dealer.

[silverarrow]

try 5 mins and £75 part aftermarket

are you sure sensor gone !!! revs should flicker and if you hold 3000 rpm it feels funny on the accel

what code via obc did you get and a few ravs need a ecu upgrade which yoyota will do free

a sensor will pick up a slight change from the normal range and if it happens 3 times ping a yellow light

i would suggest you buy a o2 sensor checker only circ £15 and a useful tool

[just355]

try 5 mins and £75 part aftermarket

are you sure sensor gone !!! revs should flicker and if you hold 3000 rpm it feels funny on the accel

what code via obc did you get and a few ravs need a ecu upgrade which yoyota will do free

a sensor will pick up a slight change from the normal range and if it happens 3 times ping a yellow light

i would suggest you buy a o2 sensor checker only circ £15 and a useful tool

Thanks for advice

Just tried it and revs dont seem to flicker -it idles just below 1000 rpm with very tiny occasional flicker only and holding 3000 rpm seems fine

I am just going by what the dealer told me , and they did reset light originally but it came on again within a few miles

I will try cleaning sensor as perhaps it is that

Can you tell me where the bank 2 oxygen sensor is as there are 2 wires 1 Left and 1 Right coming out of top of manifold and 2 at bottom aswell

[Fabio]

There are 2 oxygen sensors on these engines

1 before the cat

1 after the cat (with a special plate on this one)

The pre cat sensor is used by the ECU to control fuelling etc...

The post cat sensor is used by the ECu merely to determine the health of the actual cat itself.

faulty pre cat sensors can cause fuelling issues - such as running too rich (first you'll notice obvious rich petrol smell and the economy will take a substantial hit in your wallet and mpg) you can if you are mechanically competent change the sensor yourself. It may be rusted into the manifold in which case you'll need to skilfully remove it and possible re tap the thread or use a helicoil insert. you could weld up the old mount point and drill and re tap a new one - I have seen that done commonly.

If your post cat sensor is faulty you could choose to ignore it - it could be reporting a fault code as a result of the pre cat sensor being faulty and thus causing the ECU to affect fuelling. Best to change the important one first i.e. the pre cat one. These sensors can be had for anything from £10-£40 - yes really that cheap. you can even get quality platinum ones from the states for about £50 postage included!

you may find after a successful pre cat sensor replacement that the fault code from the post cat may go away. if it doesn't - you may choose to ignore it - but you will need to put your exhaust on to a accurate exhaust gas analyser which should tell you for certain if your CAT has actually bought it ( it might have too as too rich a fuel mixture can destroy a cat in next to no time) and the faulty pre cat sensor could have done just that...

If you are relatively certain your CAT is still healthy you can again cheaply replace the post cat sensor with an OEM replacement again for a lot less cost than a stealership would charge. replacing this one is a bit more difficult because of the mounting plate - again drilling and tapping may be required on badly rusted examples.

Hope all that helps somewhat :)

refs:

• Oxygen sensors
  
• Oxygen sensor replacement
  
• All about lambda sensors
  
• O2 sensors - how to diagnose and replace
  

p.s. ensure you get no oil or silicone near the sensor - even slight silicone residue will kill a brand new O2 sensor in seconds.