Technical O2 lambda sensor replacing

[koalar]

Ahh

Location of everything is here

http://4cardata.info/elearn/169/2/2009000/2000901/2001393/169002479/


hopefully its the same on a right hand car

 

[Theleman]

Brilliant info koalar, thank you.
I further look forward hearing from you tomorrow about your own car's wiring of the sensors, and their fuses.

My Panda is a 2009, 1.1 Eco Hatchback.

 

[Theleman]

I took the car to a garage for them to have a look at the problem this afternoon, and they checked it out.

They said that the new o2 sensors cables seem too long. It must be shortened, because the voltages the cable carry are very small, and when it is long like that, it would be lost on the way to the ECU.

Also they said, the emission is bad. It could be the air filter, or the air filter cover lid not sitting properly due to one of the bolt securing the cover air filter box over the carburettor is loose in the nut thread. The thread is damaged, the bolt is hung loose not securing the air filter box properly.

I knew that, and tried my best to secure the bolt using the rubber tape wrapped around the bolt, and securing it. But obviously it came off when the car was driven to the garage.

 

[Theleman]

I wonder, if hammering in a plastic rawlplug into the threaded hole where the bolt fits, will secure the cover tight enough. Or should I go to Screwfix and buy INTERNAL THREADED SLEEVE ROD or BAR STUD, and fit it into the threaded for securing the bolt of the cover.

https://www.screwfix.com/p/easyfix-carbon-steel-threaded-rod-connecting-nuts-m6-10-pack/728gx


I ordered a pack of Electrical Terminal Barrier Block Strip Wire Connector from Amazon, to shorten the cables of the sensors.

https://www.amazon.co.uk/dp/B08H56J...9Y2xpY2tSZWRpcmVjdCZkb05vdExvZ0NsaWNrPXRydWU=

 

[koalar]

Disconnect both sensors
Put a pin in the connector that would be opposite the outermost White cable
(mines blue and red)
Multi meter Black probe on battery negative
Ignition on
Multi meter red probe on the pin

In my case 12.15V yes I know my battery isn't good and I have taken a rubbish picture and the First 1 is behind the glare

 

[Theleman]

Great info and photos koalar. Thanks & Much appreciated !!

 

[Theleman]

Are your O2 sensors the original? Or have you replaced them?
If replaced, did you have to shorten the cables of the sensors before installing them?

 

[koalar]

No idea if they are original only had this car a few hours


You have already measured the resistance of the heater element @ under 10Ὡ there isn't any noticeable drop at 12V


Are you sure the new sensors are correct they are normally around 12 inches

 

[koalar]

They said that the new o2 sensors cables seem too long. It must be shortened, because the voltages the cable carry are very small, and when it is long like that, it would be lost on the way to the ECU.

sounds like BS to me

measure the 12V supply to the heater as above with the sensors disconnect

lets make small steps

 

[koalar]

Your fuse box is likely to be different but if I remove this fuse F11 as labelled on the inside of the cover

And Engine control system secondary loads in the handbook

The heater Volts drop to 2V pretty much the same as yours


Be the last last thing I can measure for a few days as the gearbox needs to come out so the battery and tray will have to come out

 

[Theleman]

So, F11 is for the O2 sensors?

I opened up the fuse box, but there was no F11 marked fuses. Which one could it be in the photo? Maybe it is using different number for the fuse?


And the long threaded nut for the bolt, what would be the best option to get the bolt securely tightened in the cavity?

 

[Theleman]

Would one fuse for the both sensors?

Could the very left corner on the bottom in the photo, the blue one marked as 15, could it be the one you are pointing in your photo?

 

[Theleman]

Ahhh... I found the F11 fuse from the cover, and located it.
The F11 is marked as 15 and it is the blue one, and it is BLOWN.

I checked in the front dash board for the spare fuses, but none are the BLUE 15.

 

[Theleman]

Going to pick up a pack of mini blade fuses from ScrewFix, and also a Long Rod Threaded Nut for the Air Filter Box.

The bolt size for the nut is M8 = 8mm.

 

[koalar]

I would take little steps again

There's a Good chance replace fuse clear code and all is good and it was just one O2 sensor that already change that caused it to blow

However here may be a fault present

I would disconnect both sensors replace the fuse, switch on the ignition and check for 12V and switch off


Then plug the sensors in one at a time and check if it blows again. Which I hope it won't. But at least we will know which part of the harness needs looking at.

 

[koalar]

Ahhh... I found the F11 fuse from the cover, and located it.
The F11 is marked as 15 and it is the blue one, and it is BLOWN.

I checked in the front dash board for the spare fuses, but none are the BLUE 15.

Interesting

Mine is a 10A

However the handbook says it should indeed be a 15A

Looks like mine has blown in the past and replaced with the wrong one as the wiring diagram also indicates 15A

 

[Theleman]

I would take little steps again

There's a Good chance replace fuse clear code and all is good and it was just one O2 sensor that already change that caused it to blow

However here may be a fault present

I would disconnect both sensors replace the fuse, switch on the ignition and check for 12V and switch off


Then plug the sensors in one at a time and check if it blows again. Which I hope it won't. But at least we will know which part of the harness needs looking at.

Great idea. Yes, I will take the approach. As you suggested, the bottom sensor was faulty, and when it was going faulty, it must have take off the fuse too.

So, makes sense after replacing the fuse, unplugging both sensors, and check for the 12V from the cables, and then identify which cable is still faulty, or with a luck, both cables would be sending out 12V in which case, it would good to go and clear the code, and send the car for MOT.

 

[Theleman]

Interesting

Mine is a 10A

However the handbook says it should indeed be a 15A

Looks like mine has blown in the past and replaced with the wrong one as the wiring diagram also indicates 15A

It must be OK with 10A. I read that its OK to use under rated fuse, but never use over rated fuse.

 

[Theleman]

Couldn't pick up the fuse pack from anywhere = all out of stock and it will be middle of next week they have it in stock.

So, I just used 10A red fuse, and replaced the 15A blue F11.
Unplugged the cable, and read 12V coming out. Plugged in them all back.

Started the engine, and this time, the EML was flashing.

I checked the F11 again, and the FUSE is blown again. Unplugged the cable and read for the heater supply voltage, and it was back to 3V again.

The flashing EML has never happened before.

And the new FUSE although 10A rating, it is blown instantly, when the engine started??? What could this mean?

 

[koalar]

Couldn't pick up the fuse pack from anywhere = all out of stock and it will be middle of next week they have it in stock.

So, I just used 10A red fuse, and replaced the 15A blue F11.
Unplugged the cable, and read 12V coming out. Plugged in them all back.

Started the engine, and this time, the EML was flashing.

I checked the F11 again, and the FUSE is blown again. Unplugged the cable and read for the heater supply voltage, and it was back to 3V again.

The flashing EML has never happened before.

And the new FUSE although 10A rating, it is blown instantly, when the engine started??? What could this mean?

The only things connected to F11 is the O2 heaters and the vapour solenoid


The heaters are only 2A each. No idea how much the vapour solenoid is.


Any new codes logged ?