£30 to clear Engine Management Light

400ixl

Equally charging for doing something like that (basically nothing) for a regular customer is a good way to lose repeat business. The towbar example, I would have offered a payment as well, as they provided a proper service, being a walk in and them actually providing a fix they should be charging, even if it is a reduced rate to gain business.

Happened to chat to a couple of garage owning friends this evening and asked if they would charge a regular customer for doing what the garage did for the OP. First up they said they would give a proper explanation for why they felt just resetting it would not result in it coming back on again and secondly they would not charge a regular customer. Walk in by someone with an unknown car would be different. They also said that they get more recommendations to new customers through doing this sort of thing than it could ever cost. So the opposite to the supposition posed by some.

Anyway, we are not going to agree so will leave it there.

If I was the OP I would still be finding an new garage.

Goudy

You are paying for more than time.
Garages have overheads and believe or not, experience.

As for just clearing the code and turning the light off, that's quite a common reaction to some error codes.
It's part of the diagnostics to see if the fault returns or if it's just an blip in the system particularly fuelling issues, as they can come and go and the system counts up the times it detects the same problem before lighting the EML.

I would have been surprised if they hadn't just turned the light off and sent you on your way with a reminder to bring it back if it happens again.

I'm sure you'd be less happy if they decided it needed a load of expensive work on the evidence of one EML or even some more expensive diagnostics to decide if it needed an expensive repair.

My old Alfa used to set the SRS light off whenever the seat was moved with the ignition on.
I didn't have the specific tool to read the SRS ECU so took it to my local indie Alfa/Fiat specialist.

He charged me to reset the light.
The fix was to pay to strip the seat's airbags and seat belt pretensioners out and replace them and part of the cars loom to the seat connector.
As the other half wouldn't listen to only move the seat with the ignition off, I ended up paying three or four times, but it was still worth it compared to the thousands it would cost to rip it all out.

Eventually I did run out of patience and chopped the loom of both the car and seat wiring back and fitted a better, more robust connector with a little extra wire to take the tension off when the seat was moved.

Mildly_Miffed

For less than £30, you could have bought your own eOBD reader and read/cleared the codes.

Would you have known what they meant?
Would you have known whether the car was safe to continue to drive or not?
That's what you're paying for.

Username03725

400ixl said:

Equally charging for doing something like that (basically nothing) for a regular customer is a good way to lose repeat business. 

Being a regular customer doesn't entitle anyone to an expectation of discounted or free work. I use the same regular garage to look after all of our family cars and have a very good relationship with the two owners, but that doesn't extend to me expecting them to do quick jobs for free. I'd rather pay anyway, even if - as has happened occasionally - it's a token £20 just for helping out. Time spent on quickies is time lost on paid work.

DjangoUnchained

The engine warning light comes on as a generic warning, you can clear it and it will probably come on again at some time or you might be causing damage to the engine.  I believe clear it once, if it doesnt come on again fine. But if it does come on either get it diagnosed properly at a garage or try and diagnose yourself via the OBD.

Bigwheels1111

£30 what a bargain, where is your garage. I would like to use them if they were local to me.
Main dealer wants £150 minimum.

As above, buy a £12 obd2 reader from say Amazon, plug in read code, note down code number.
Clears codes, light goes out, your all done.
If board look up code on google.

I had a Nox code put my light on, sensor is in the exhaust.
AA came out and scanned the car, he cleared the code, guy said if it comes back get a cheap scanner and clear it yourself. So I did.
Been fine for 4 years now.

Mildly_Miffed

Bigwheels1111 said:

I had a Nox code put my light on, sensor is in the exhaust.
AA came out and scanned the car, he cleared the code, guy said if it comes back get a cheap scanner and clear it yourself. So I did.
Been fine for 4 years now.

Well, no, it's not been fine. The sensor hasn't miraculously mended itself.

You could just replace the faulty sensor. Radical thought, I know.

531063

As a general rule of thumb if engine management light comes on and the is no loss of power ignore it, obviously if the is a loss of power get it checked out.

Mildly_Miffed

531063 said:

As a general rule of thumb if engine management light comes on and the is no loss of power ignore it, obviously if the is a loss of power get it checked out.

Nope.

When I bought the current daily last year, it was throwing a pre-cat lambda fault code. 2012 diesel.

No EML. No ill effects driving it. Nothing to notice, unless and until you read fault codes - and that would come back regularly if cleared.

So I changed the lambda.

+4mpg.

Goudy

With modern fuelling systems, there's generally a safe, keep you moving mode programmed in.
It tends to be overly rich as running too lean can cause some damage.

So a modern petrol car with start up on a preset set of values from within the ECU to get you up and running. It'll ignore most sensors and throw in a set amount of fuel to get it to fire up.
This is called a closed loop.
Earlier systems ran like this until the engine produced enough heat to heat the O2 sensors up fully, but modern O2 have their own heater elements built in so switch to variable fuelling strategy a lot sooner which is cleaner and a lot more efficient.

This variable fuelling strategy is referred to as open loop.
The car is now measuring air speed or density, manifold pressure, engine temp, ignition timing/knock and exhaust gas to determine it's fuel delivery strategy based on the demand.

Most of the sensors it uses are expected to return quite a variable set of readings.
Anything from engine off/ignition on to wide open throttle at top speed in a range of conditions, so spurious readings can happen from time to time.

The values these sensors deal with are very small, often the ECU sends a 5v signal to the sensors, the sensor alters that 5v in some way and returns that altered signal back to the ECU where it looks up what to do with that value.

The O2's self generate an electrical value back to the ECU, somewhere between 0.1v and 0.9v.
It doesn't take much to interfere with those signals, a damp, corroded or tarnished connector, loose connector over a bump or splashing through a puddle and soaking a connector or a drastic change of load on the electrical system can cause spurious readings.  

Generally there are two different sensor faults, broken sensors that have a failed circuit, no need to explain that to the ECU or an unexpected reading that is out of range.
With fuelling it general takes  three or so detections in the same drive cycle to flag these unexpected readings with a EML.
Trouble is if you switch off and restart, the process starts all over again and you may never reach the point where is detects three in a row, so no EML.

Usually with either of these the fuelling will now reverts to closed loop-system fault.
It's a similar set of preset values to the cold start ones but you'll generally use more fuel and the engine will run heavy or a bit rough, otherwise it might appear to run ok but perhaps restrict the full turbo boost of a turbo engined car.


These days these fuel system faults might not be linked to the main EML but to a fuel system warning light.
These have been common in modern diesels for a while, sometimes they are linked to the glowplug light and you might notice it flashing every now and then, it's a something isn't right at this very moment but it can't determine what sort of warning.
You might suffer it if there's a cold snap and your fuel is sluggish, the filter is starting to clog and you are demanding a lot of fuel quickly. Not so much a fault as a set of unfavourable circumstances.

So you can see why a garage might clear a fuelling related code and send you on your way.
Sure there's a good chance it might come back and a slimmer chance it won't, but it's the returning hard set code that helps identify the issues.