blader1611

The 2 codes above say one is the oxygen sensor (bank 1,sensor 1) and the other is the ignition coil B, primary control circuit low. Car doesnt seem affected by it other than a very slight hesitation now and again and it really is very slight almost imperceptable. Anyone got any ideas what this is and would i stand a chance of repairing it myself? Any inof\advice would greatfully received.

blader1611

Ok so it looks like i need a new Lambda sensor but some people have suggested trying to clean it first. Question is where the heck is it? Its a pre-cat sensor if that makes any difference.

RichieST

iTrader: (2)

The sensor is in the exhaust, there's one before the cat (which has failed) and one after. Cleaning it won't work, afraid it's replace only really.

blader1611

I can see 2 sensors in the manifold sitting side by side (peering over the engine). i cant find anywhere on the web which tells me which one is bank 1 sensor 1.

RichieST

iTrader: (2)

You only have 1 bank, V6 engines that have 2 manifolds have bank 1 and bank 2. Sensor 1 is the pre-cat sensor, sensor 2 is the post cat sensor. Can you get a pic of what you can see?

blader1611

sorry about the orientation. These are the two sensors that I found, the one with the blue sheath goes straight to a green plug about 6 inches away just out of shot. The one to the left (bottom one on this photo) seems to go all the way round the front of the engine in a protective cable tidy type thing and comes out above the green and blue plug. question is which is sensor 1? The bottom photo does seem to show the blue plug has its lead heading off to the rear of the car so can I assume thats the post cat? If that is the case what is that other sensor on the top photo next the the blue sheathed one that heads to the green plug?

RichieST

iTrader: (2)

Your pictures don't seem to work, but does it look anything like this?



You can see sensor 2 fitted after the cat, the hole you can see before the cat just after where the 4 down pipes meet is where sensor 1 goes.

blader1611

I shall work on the photos and post them up. No it doesnt look like that, i shall try and post the photos as I am not eloquent enough to describe it.

blader1611

Ok I have absolutely no idea how to add a jpg. Let me look for the instructions.

RichieST

iTrader: (2)

Email them to me and I'll have a look and post them if not sure.

richy-3000@hotmail.com

blader1611

CBenno

Unplug one of them and run the engine with the diagnostic tool connected it should say somthing like bank 1 sensor 1 open circuit or a fault for which ever you have unplugged

RichieST

iTrader: (2)

That's odd, i've never seen 2 sensors mounted side by side like that before. I'd have an educated guess and say it'll be the one with the blue sheath that goes to the green plug.

blader1611

Yes RichieST it has me stumped as well. i have trawled the net for days on end now to see if i can track this down and not a single answer anywhere. It seems you can only have one before and one after the cat yet i seem to have a "spare"! Its driving me crazy, given the cost of these things I dont really want to get this wrong. i could take it to the garage but that is costly and no fun at all. The search continues....

blader1611

CBenno, would that cause any issue if i have the engine running with the sensor unplugged? By the way how do you free the plugs from the metal mounting bracket?

RichieST

iTrader: (2)

It will cause no harm to the engine running with one disconnected, when the light comes on on the dash it logs the fault code and puts the engine into limp mode, which won't cause any harm but you may notice a loss of power and MPG. To clear the fault codes and return the ECU back to normal operating mode, it can be done either through a diagnostic machine or by disconnecting the negative lead off the battery for half an hour.

blader1611

The only evidence I have is that sensor 1 is supposed to be the pre cat sensor (sensor 2 is post cat, would you agree?) (general opinion on the net) and if you look at say eurocar parts the new sensors on there which have a green plug say that this is the pre cat. This ties up with the DTC reading but that other sensor is a spanner in the works. The other DTC code I am getting is related to the coil, if the coil was faulty could that give me a false reading for the lambda. Coil is cheaper to replace so is it worth chnaging that first. i assume the two codes are related.

RichieST

iTrader: (2)

If the coil pack has failed, then you will getting unburned fuel through the exhaust which could contaminate the lambda sensors and cat. Maybe change the coil pack first, slear the fault codes and go from there.

CBenno

U see the smaller tab in the centre of the bracket bend it out a bit with a flat screwdriver and pull the plug down or up which ever way frees it then unplug the connector it will still run ok as the ecu will use default settings as it will still be getting some readings from the likes of the airflow meter and water temp sensor.

CBenno

There will be one sensor for cylinders 1 and 2 and the other will be for 3 and 4

blader1611

CBenno, if that is the case why do they go to different plugs? the one one the left seems to go all the way round the engine and then wires seem to divide between the two plugs and go in to the top of the plugs? The one on the right goes straight to the green plug from underneath.

blader1611

I have found several coils for focus mk2 1.6, can anyone definatively tell me which one i should buy or even a part number?

Greasenuts

Ive seen this set up on a couple of jap cars. You remember I mentioned the whole "bank 1/bank 2" thing in our other conversation, well thats applicable here aswell. Bank 1 always refers to the bank of cylinders which includes cylinder number 1. I realise that we're not strictly dealing with banks in a 'V' formation but cylinders 1 + 2 are to be considered as bank 1 and cylinders 3 + 4 are bank 2.
Assuming Ford number their cylinders in the conventional way, your faulty sensor is the one to the right of the picture. (driver side of the car).

I hope this goes some way to clearing up your confusion.....

Greasenuts

Sorry, I meant the left of the picture. (Still driver side though)

blader1611

Thanks Greasenuts.The HT leads are numbered and no.1 lead is at that side of the engine so i assume that must be cylinder 1.
I was hoping you weren't going to say that one. This is the one where the wire goes all the way round the engine in a cable management tidy that contains other cabling and it can only be opened by cutting it out, that equals "nightmare". Am i best buying the non direct fit and splicing the wires together (I think it comes with kit for this)? Could the coil (dtc P2303 fault) be causing a false reading for the sensor?

blader1611

By the way i did speak to a ford dealer who were a little bit helpful but not exactly clued up. They said there are 2 cats so there are 2 pre cat sensors which is what i found. I told him which sensor it was based on what greasenuts had said and he said they dont sell that sensor with a long lead on it! Why do you put it on the car then i told him. "I dont know" was the response. God help us.

blader1611

Just a bit of an update but i have now found that the sensor on the left does not go all the way round the engine bay, in actual fact there are 2 plugs tucked in by the engine bay that I had missed. This at least makes it easier to replace.

Greasenuts

hi mate sorry ive been away a while. glad to hear your getting somewhere. i would've been surprised to find the wiring as awkward as you suspected.
As for the why the coil fault code is stored, who knows, it could be from a previous fault perhaps and not yet cleared itself...! I dont think it would manifest itself as "slight hesitation now and again", i think thats more likely related to the faulty oxygen sensor!
In your position i would like to view the live data from the sensor to back up the fault code, however, thats not really something i would like to try to explain on here...!