First Problem - Engine Warning Light

[skirmish]

"Good Luck" - Thanks for that. I'm sure I'll need it!

Anyway, as you suggest, hopefully someone else will come along and give some more detailed advice on how to solve my problem.

Dave

[skirmish]

Sorry to bump my own thread but I'd be grateful for any more advice regarding this P0125 error message.

Hope someone can help.
Dave

[skirmish]

Oh, I found this written in a Lexus forum:

"You do NOT have a coolant problem. The po125 is a original obd2 code and is very misleading but was never change. The code should read <PO125 Insufficient Temperature For Closed Loop Operation. Your problem is going to be in you O2 heaters (frt bank)."

and this



You need someone who knows to confirm this info though.

Good luck.
  s:D s:D

I could still do with a bit of guidance please.

I gave the MAF sensor a good clean and did a reset using the code reader. I went out in the car today and thought everything was going to be okay.................
Until, the warning light came back on again. I have at least ruled out the MAF sensor though I think.
So is the advice above the next place to check and is there actually any way that I can check the o2 heaters?  What exactly does FRT bank mean too?

Sorry for all the questions but it's steep learning curve at the beginning especially when I've been used to just jumping in my Focus and using it!

Dave

[Wabbitkilla]

There are specific codes for the O2 sensor heater circuits failing....
 l viewtopic.php?f=46&t=12480 l

I seem to remember a poor earth somewhere on the engine can cause this code too.
The code description is so wishy-washy it's difficult to say if it's associated with one bank or the other.

the description suggests one of the causes could be a short circuit in one of the oxygen sensor heaters. If you have a multimeter you could check for this quite easily by unplugging the sensors and measuring the resistance between the black wires on the plug. It should read around 18ohms I believe, if it's a short then you know you need to replace that sensor.

[skirmish]

Thanks for that. When you say 'bank' do you mean either the left or right hand sensor that I can see when I look down on the engine?

I do have a multimeter so I can certainly do that test.

Dave

[Wabbitkilla]

That's right, Bank1 is the right hand side, Bank2 is the left.

So right is Bank1 Sensor1 (B1S1), left is B2S1, then the one after the catalyst is B1S2.
There's a post in the technical section that shows you the pictures.

[skirmish]

Thanks for that. I'll get the multimeter on them tomorrow sometime. Hopefully it will throw some light on the problem.

Incidentally. Would a professional diagnostics/reader give the precise details of what is wrong or does it just produce a code number (in this case rather vague) like my reader does?

[skirmish]

Well I've just measured the impedance on the top two o2 sensors. The right hand one measured 13.8 ohm and the left one 15.3 ohm. Do you think these values are okay?

Should I also now measure the third one too? If so I'm not sure that is and how to access it. I've looked in the relevant Tech Section but couldn't see any reference of it.

Do I need to access it from below or does the lead end up in the engine bay where I can measure it there?

Thanks, Dave

[Wabbitkilla]

They sound pretty much ok to me, the connector for the third o2 sensor is attached to the left side of the coolant expansion tanks, so you can unplug it there and test   s:wink: :wink: s:wink:

[skirmish]

Ah, so that is where it is!

Right, just managed to get my fat fingers in that area and have now tested that one too which reads 15.5 ohm. So can I deduce from this that all the o2 sensors are okay?

If so can you suggest what I should be looking at next to try and find the problem.

[skirmish]

Just been to see a car electrics specialist and he connected the MR2 to his diagnostics machine and would you believe it the car wouldn't talk to it! I did tell him the code my reader had produced and he's pretty sure that it's going to be the right hand o2 sensor. He did point out that the left hand one has already been swapped at some point. His advice was to switch the two sensors, do a reset and then wait for the warning light to come back on. He then expected the code to be either 0124 or 0126. If this happens then it points to the right hand sensor being the problem.

My problem now is to remove the sensors and I immediately see that my conventional socket set is not going to work. Can anyone please suggest a good source for a sensor socket and also what size will that need to be.

Thanks, Dave

[Anonymous]

Your local motor factors will have one, about a tenner. Often called a lambda socket. I think there only is one size.

Just checked mine, Draper 22mm Oxysensor socket.

[skirmish]

Thanks D!ck. Just ordered one from ebay. I'm sure it will be a useful addition to my collection of tools.

[skirmish]

So, in anticipation of the sensor socket arriving (which it did this morning) I've been squirting some PlusGas onto the sensors to hopefully make removing them easier.

It doesn't seem to have worked though as the first one I've attempted to remove is proving rather stubborn. I've applied quite a lot of foce but not sure quite how much to use as I'm worried 'something bad' may happen.

At the back of my mind is the sensor that had to come out of my partner's RAV 4 and the garage doing that damaged the thread and the new one had to be welded in place!

Any thoughts or tips for this sort of problem? Also would it be better to it when the engine is warm/hot?

Dave

[Wabbitkilla]

A bit of warmth tends to help, but they can be awkward little burgers!
You'll probably break the socket before you do any real damage ... probably.
Persevere

[skirmish]

Success!
Another squirt of PlusGas and then a little bravery using an extension bar on my socket.

[skirmish]

So, as advised I removed both o2 sensors and swapped them round.
Just been out for a drive on some of my favourite local country roads and was expecting the Engine Warning Light at around the 10 mile mark like it normally does. Ariived home having done 20 miles and no sign of the warning light at all.

I'm not complaining as it now all seems okay but can anyone possibly suggest what's going on?

Dave

[Toplesscouple]

CEL may not appear on the first run. Think it has to go through two cycles from start up. Quite possibly wrong though   s:) s:)

[skirmish]

Well it seemed to only need one cycle when I did a reset with the sensors in their original position. It's had two good runs now and still no warning light. Fingers still crossed!