Hi All,
A few days ago my engine management light came on - checked the dashboard diagnostics - dtc said no faults. Took it to my local garage and they plugged in their scanner and said the lambda sensors needed replacing - had this done (£200) - problem is the light came back on. took it back and they say that it must be a wire between the sensor and the ecu as the sensors are ok but the car reports the sensor - post cat I think - is not heating. Their solution was to remove the management bulb as they were unable to trace the wires.
So:
1. If there is no heating to the sensor is this a major issue?
2. Should I take to Ford and let them have a play?

Obviously I'm slightly concerned that the bulb has been disconnected since now I have no way of knowing if anything else is wrong unless I buy a £20 scanner from eBay - are they any good - and do a monthly check.
Any advice gratefully received.

 

First: never go back to this "garage".
Is the Oxygen sensor replaced by an original Ford one? or some aftermarket make?
Aftermarket sensors have a lot of problems with heaters because the resistance can be different.
Usually this is a sensor fault. Sometimes wiring, voltage supply (fuse?) or rare but not impossible, the ecu itself.
Do you have the number of the fault code?

 

Bloody cowboys! How did they take the bulb out? The management light is an LED soldered to the circuit board, so get them to put that right first.

And were both sensors replaced? If so, why? Surely it was either one or the other. Is it an ST170? A genuine sensor from Ford was around £50 as I bought one a couple of years ago, a doddle to fit too!

 

Thanks for replies - I'm not going back - the light came on so I went to my local place as I didn't want to drive too far with the light on. They told me the sensors had failed (both) - they showed me the one's they took out - they were bendy and in poor condition so I assume they were faulty. When I got the car back the light was off - it had been reset but it came back on when I next started the car - they had a look and said the fault was the heating circuit - probably the wiring. They spent all morning on it - no charge but when I went to pick the car up they said they had turned off the EML - not sure how they did it - I assumed it was the bulb. Answers to questions:
1. They are aftermarket sensors.
2. Which fuse should I check?
3.I don't have the fault code -will get this from them tomorrow - hopefully when they renable the EML.
4. Yes it's a ST170 - 2003 model, 73,000 miles.

Hope this helps - will post updates after I've been back tomorrow!

 

Does the management light come on when you turn the ignition on? Best bet is to get the fault code and go from there.

 

Obviously at the moment it doesn't come on at all - but yes it used to come on straight away. The dashboard diagnostic always said none for the dtc codes - but after researching the forums it appears this isn't reliable - not sure if the £20 one's on eBay would work?
Don't think there is a fuse in the lambda circuit.

 

I've got one of the fault code readers from ebay, works fine! I'd be getting it back to the garage to get them to re-instate the light. If the sensor isn't working properly then your fuelling will be out so it can knacker the cat and fail MOTs, and then you will have a bigger bill!

 

I believe he said the sensors are working fine - just the heaters which have no effect when the engine is up to temp so he reckoned it was a minor issue.
Must get the EML back on though - as you say could cause issues later on......

 

The Oxygen sensor before the CAT will make your car run shite if its faulty, the sensor after the CAT will not make a difference to the economy or running of the car. Sounds to me like they fitted cheap sensors, i swapped my Pre CAT sensor recently, took 10mins to fit the bosch part that cost £80 been perfect ever since.
You cannot read fault codes from the dash it does not work you do need a fault code reader. I use my old Bluefin Handset to read and clear the codes on my ST170
You can clear codes yourself by simply disconnecting the battery for 20mins when you turn on the car after this your dials will sweep indicating a reset

 

Thanks - disconnected battery - light off. Stopped for 30 minutes in town, restarted light on - that's when I took it back. It runs ok ish at the mo. I went back this am and got my EML bulb and holder back - I'll fit it this weekend. Monday am it is into Ford garage for diagnostic check - £60 + VAT including 1 hours labour - hopefully they can give me a full report - they've quoted £140 ish for each sensor - I've seen NGK one's on Ebay - are they any good....

 

Ouch, that's a stupid price! How come the light is now working if they have taken the bulb out?

Cancel the ford's diagnostic check and get yourself a code reader off ebay.

 

That bit about the bulb was before I took it back - after it spent all day there they said they had disbled the light. After last nights reading I went back this am to find out how to re enable it - was given my bulb and bulb holder from the toolbox - decided I'd fit it myself......

 

Ouch indeed on the price to read a fault code. If you was local i would have happily read the code for you for free. NGK is ok Bosch is better.

 

Back from Fords - £72 lighter in pocket - they have confirmed that both sensors heating elements are shorted to ground. They want another couple of hours to check the ecu and wiring - if ecu then it's easy but expensive, if wiring they have said they will sort and charge the 2 hour fee. Helpfully they also included a health check which according to their price I need a further £1400 of work - tyre, shock absorbers, discs etc. I'll get a second opinion on this.......

 

Thanks for all the advice - I decided to snoop around myself a bit. Started with oldford's advice - looked in book and sure enough there is a fuse - it's 10A one in the engine compartment (F18 I think) - checked it - blown. Figured this was because of the short to earth Ford reported - replaced anyway having left battery disconnected overnight. Been running the car all day - left parked for 4 hours etc - still no light so I think it's cured. Went back to first garage and they held their hands up about not knowing there was a fuse but were sure the sensors were faulty (they were very bendy when I saw them) and thought they ccaused the fuse to blow - they were happy it was fixed. Not sure what to do with the Ford main dealer - surely they should know about the fuse....

 

Glad it's sorted, my bets were Ford knew the fuse was blown but chose not to replace it to give you a big bill instead!

 

Thanks - I'm glad too - will be finally happy if it doesn't come on tomorrow morning after being parked all night. Think I'll head over to Ford to see what they say - as for the rest of the work they reckon needed doing I've had it looked at and the local garage can sort it all for less than £500 - Ford put a red alert on the fact that one of the wipers was smearing and quoted £33!

 

I always use a small garage that used to be local to me. I now live about 15 miles away but always go back there as I know any work that needs to be done will be done properly and not by the main dealer's apprentice, and the prices are far cheaper!