02/lambda Sensors.

[dodgy_damo]

My newbie question!

I've been driving an Auto 2004 Toyota Avensis petrol 2 litre (tspirit) and have had the EML come on and three fault codes come up for 3 of the 02/Lambda sensors.

Im planning to replace all 4 and it seems they are not cheap- circa £120 +VAT from Mr T.

I've searched the site and it seems that some have used Denso branded sensors from europarts..though I've searched through the online site and only two of the Denso sensors showed up coming in around £80 odd each.

Any advice on what you should buy or is it a case of swallowing the toyota prices?

Thanks

[ents]

Denso made the original sensors for Toyotas. You should buy Denso sensors, the wire length and plugs are correct. The only difference between the Denso sensors and the original Toyota sensors is that Toyota sensors have a Toyota mark on them, the Denso sensors haven`t.

The upper ones have product codes 89465-05100 and 89465-05110

and the lower ones 89465-05120 and 89465-05130

Just for curiosity, what were these three fault codes. Usually if one of the sensors stop working, the others malfunction as well. May be we can help.

Sorry for my bad English

[dodgy_damo]

hi Ents

Thanks for your reply.

I had three fault codes..i didnt jot them down, buit off memory it was upper sensor on bank one, upper sensor on bank two and one of the lower sensors. Mechanic recommended changing all 4 (he's trusted) as he said its a pain to get to lower ones so may as well change both.

is your suggestion to change one at a time and see if all the other codes go as well?

Your English is great :)

[ents]

Hi again.

Too bad you didn`t write them down, i need the exact fault codes like P0153 O2 Sensor Circuit Slow Response (Bank 2 Sensor 1) or P0132 O2 Sensor Circuit High Voltage (Bank 1 Sensor 1)

Can you read the codes again, otherwise i can`t help you.

[alan333]

I'm with @ents here, ie if one sensor is faulty it'll affect others. I'd change the upper one on the side with the two faults and see what happens.

[dodgy_damo]

I'll have to get it on the code reader again.

Do you know if the denso oxy sensors are direct fit or do you have to cut the plugs off?

and any suggestions of sites to buy them? A quick Google came up with one's at £66!

[ents]

Yes, Denso makes direct fit sensors and about £66 is the correct price.

[dodgy_damo]

hey Ents...i picked up a cheap code reader off eBay.

I only had one code come up P0037- which I've cleared. (Bank 1 sensor 2)

I guess I can replace the one and see if any other codes come up.

Its strange the other two codes arent showing now?

[ents]

P0037 means - Oxygen Sensor Heater Control Circuit Low Bank 1 Sensor 2

First check the wires (if you allready haven`t done that), it just might be poor connection. If the wires are OK you should replace the sensor. 89465-05120

Here`s a nice picture to make it easier to locate.

And how it should look like, it must have two clips on the wire to secure it.

Best of luck!

[perdaniel]

There are other possible reasons for this error code than a failed heater in the lambda sensor. According to the manual (RM1018E) it could be the EFI relay, the ECM, the wiring harness or the connector, but I think the heater is the most likely suspect. I have a T22 with the same 1AZ-FSE engine, and it has always been the heater in the sensor that have failed. It is easy to check the heater, see the attached picture.

[dodgy_damo]

Ents/perdaniel/Alan...Thanks for the swift replies.

I'll get under the car today and have a look around.

Just out of interest have you guys removed this bottom sensor yourselves in the past (just seeing if it's something I can do). Will a socket set cover it, or do you actually need the sensor socket and lots of WD40?

Im a bit concerned about access- especially when seeing how accessible the top sensors are! Sigh :)

[2rand]

Hi to ents or anyone

I have a toyota avensis 2.0l 2001. Lambda sensor issue. Codes are P 0141/ P0155/ P0161.

I would. Like to know how do u which sensor is which. I've been looking at articleson the internet and the club here and phone toyota. So question. If I'm sitting in the drivers seat is bank one the left side and bank two rightside.

As far as i know now bank two number two will be right hand lower. If i now stand and face the engine. It is now on my left Lowe one. Is this correct. Help please.

Next. Has anyone got part numbers for the four sensors. Are they all different part numbers.

Will appreciate so help. I know that this topic has been discussed. Sorry. About that.

[perdaniel]

Ents/perdaniel/Alan...Thanks for the swift replies.

I'll get under the car today and have a look around.

Just out of interest have you guys removed this bottom sensor yourselves in the past (just seeing if it's something I can do). Will a socket set cover it, or do you actually need the sensor socket and lots of WD40?

Im a bit concerned about access- especially when seeing how accessible the top sensors are! Sigh :)

I don't think that a regular socket will work (as there is no opening for the wires). You could try with an open 22 mm wrench, but buying a O2 sensor socket is cheap compared to having to buy a new sensor because your wrench slipped and ruined the sensor. I wouldn't use WD40, in my experience it's not a good penetrating oil. I have had the best results using CRC-MoS2 or some other penetrating oil that contains MoS2. Accessibility is a problem, yet a reason to buy a proper O2 sensor socket, I had to jack up my car (using a hydraulic garage jack), put it on jack stands, and remove the cover(s) (I can't remember if I had to remove one or more) under the engine to reach the sensors.

[ents]

Hi to ents or anyone

I have a toyota avensis 2.0l 2001. Lambda sensor issue. Codes are P 0141/ P0155/ P0161.

I would. Like to know how do u which sensor is which. I've been looking at articleson the internet and the club here and phone toyota. So question. If I'm sitting in the drivers seat is bank one the left side and bank two rightside.

As far as i know now bank two number two will be right hand lower. If i now stand and face the engine. It is now on my left Lowe one. Is this correct. Help please.

Next. Has anyone got part numbers for the four sensors. Are they all different part numbers.

Will appreciate so help. I know that this topic has been discussed. Sorry. About that.

Hi

You are absolutely right about which side is bank 1 or 2.

Yes, all four sensors have a different part number, because the wire lenghts are different. But in your case i think the sensors are working fine. You codes are heater control-circuit malfunction. Only bank 1 sensor 1 seems to be working. I think you have a wiring issue, hope this helps to sort it out.

[2rand]

Thanks for the reply. I think I may need anot auto electrician. Wire seems more difficult then changing sensors. I bought one sensor £88. Taking it back. I also found some for cheaper. So will try check wiring first then take it from there.

[Konrad C]

I have read through this discussion with interest and there have been some great answers, especially Ents (Henri's) showing the position of the sensors. This is always confusing.

Wayne has three sensors showing faults and Henri thinks it is a wiring fault!

There is a way of check the sensors by measuring the resistance of the heated circuit of all four. I did this with my sensor last year. I got a good sensor from a scrapper and did a resistance check on that, the intermittent one on my car, and the old faulty one I replaced years before. Now if the 3 sensors show a different reading to the one good sensor, then change them. I would change the 4th too!

The heated circuit wires and terminals are the same colour for two of the wires.

There are reasons why I would go down this route - it should confirm the sensors are faulty, eliminate or confirm there is a wiring fault, the age of the car mean the sensors probably need changing.

I have a cheap code reader and a book of code definitions. My car is not compatible, but I have used it on other cars. These Pxxxx code definitions are also available via web search.

Perdaniel is right about O2 sensor tools.

As I said this discussion has been very informative.

Konrad

[ents]

By wiring fault, i didn`t mean the sensor wires, i meant the wiring from sensor plugs to the ECU or some junction connector. As seen on the diagram, +B from every sensor eventually becomes one, also E1. I really don`t think that three sensors can brake down the same way and have the exact same fault code "heater control-circuit malfunction", that would be odd.

[perdaniel]

By wiring fault, i didn`t mean the sensor wires, i meant the wiring from sensor plugs to the ECU or some junction connector. As seen on the diagram, +B from every sensor eventually becomes one, also E1. I really don`t think that three sensors can brake down the same way and have the exact same fault code "heater control-circuit malfunction", that would be odd.

That is exactly what has happened in my car. The only difference between the trouble codes in 2rands car and mine is that I have P0135 instead of P0155, we both have P0141 and P0161. I have also replaced these sensors with working second hand ones several times, and it is always the same thing that happens: The heater element in the sensors break. It is not the wiring, I have checked that by measuring the resistance of the elements, not only at the plug but also close to the sensor using wire piercing test probes and my multimeter. When so many have failed in the exact same way in the 45.000km I have owned this car I suspect that there is something else that is wrong. The problem is that no other trouble codes show up.

[perdaniel]

Thanks for the reply. I think I may need anot auto electrician. Wire seems more difficult then changing sensors. I bought one sensor £88. Taking it back. I also found some for cheaper. So will try check wiring first then take it from there.

I have attached some relevant images from the manual for the 1AZ-FSE in the first generation Avensis (RM783E). According to this you should check the engine ECU first and the oxygen sensor heaters second. In the manual for the same engine in the second generation Avensis they have reversed the order, which makes much more sense as it is easier to check the sensor heater than checking the ECU. You will also see that they have switched "OK" and "NG" on step 1.

[Konrad C]

By wiring fault, i didn`t mean the sensor wires, i meant the wiring from sensor plugs to the ECU or some junction connector. As seen on the diagram, +B from every sensor eventually becomes one, also E1. I really don`t think that three sensors can brake down the same way and have the exact same fault code "heater control-circuit malfunction", that would be odd.

I see understood what you said, but it is easier to check the sensors than trace a wiring fault back to the ECU.

After 14 years things like sensors can and do fail, like coil packs, and they can fail simultaneously or one at a time.

Perdaniel has posted the readings for the heater circuit, and that is how I tested my sensor which confirmed it was faulty. My car is the earlier leanburn, but the test is exactly the same. You don't want to buy a sensor if none are faulty. That was my point too!

The colours of heater wires I was describing, are on the sensor itself for the purpose of the resistance test.

Perdaniel's post says everything I have said in my earlier post and this. I admit his is more to the point.

[dodgy_damo]

I just wanted to thank everyone for their help.

Apologies for the slow feedback.

I bought and fitted the one Denso sensor off eBay and it cleared all the codes and No more EML.

So thanks for helping save me money lads!

[toylexus]

Hi guys, I had similar problem,  replaced two sensors and a week later same fault occurred.

Auto electrician says unused fuel hitting sensors so currently looking at the cause but baffled just now. get the odd hesitation, replaced plugs and coil packs but still the same.

[dodgy_damo]

Toylexus...The one sensor was replaced. Second one about 6 months later. Ive done the third one and have the fourth to do (EML back on)- I guess its a matter of biting the bullet on these in the end- Mechanic replaced first two for me. I did top one myself, just bottom one left (mechanic is doing it for me next week and clearing codes)

[m456an]

Very interesting thread....though I can only see one o2 sensor at back off engine, does my car have only 1 upstream?

[Luv]

I have a 2005 auto T spirit 2.0L avensis. Mice managed to enter the engine area and chewed half of the 4 wires to the 1st coil pack near the oil tank cover. If i get a replacement wire with the connector do the colours matter when joining it with the half left in the car?