I’ve owned my 2022 2.0l diesel since new, now done 16,500 miles. I’m retired so don’t use it a lot. It hasn’t had a good run for a few months. The emission lamp has just come on. Could it simply need a decent motorway run? Will I learn anything from a lowish cost OBD Reader (any recommendations?). Or is it best to seek help from nearby Indy garage?

It'll need a diagnostic check to see if any fault codes flag up. Are there any other electrical gremlins? I ask because if there are this could be a low battery that's the cause. 

Hello David,

Could be worth giving it an Italian tube by keeping the revs around 3k plus for at least 20 mins. Only costs some fuel. 
Regards,

Gareth. 

Thank you, both. Could be low battery as I hadn’t driven the car in a while. Yes to other gremlins. Pre-sense large icon came on for apparent reason and it also flagged low tyre pressure. Checked and all 4 same reading on gauge, but I’ve reset it.

My wife had an Audi TT and battery drain was a common reason for spurious warning lamps.

I’ll give the battery a charge and then take the car for a run, fingers crossed.

Hello David,

Different symptoms now, which suggests a sub standard battery as being at least a contributor. I would recommend you get this checked before moving on.

This car seems to have been built during Covid, and likely to have been sitting around for months - not good for batteries.

Yes, charge it by all means ( using an ‘intelligent’ charger) and see if you have any reduction in symptoms. If so, it may be worthwhile getting the battery professionally tested - Halfords stores can do this. If it is eventually declared to be substandard then please come back to us if you have respect for your wallet, and we can give you some pointers for good deals.

Regards,

Gareth.

Looks just like a normal EML light to me.  You need error codes read. 👍

 

Emissions light is completely different.  Apologies if not , Audi is new to me. 💖

 

 

Edited October 12, 2025Oct 12 by Audisq524
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Agree with Audisq524. The picture is showing the eml on. This could be caused by the battery so suggest first ensure that it is fully charged. A new battery will need coding to the car. A fault scan will give you more info. The OBD reader I have is an OBDeleven bought about 5 years ago and has worked well on various VAG cars (Seat, audi, vw) over that time.

Thanks for the replies. My manual shows it as Emission control system

Battery now fully charged. I’ve started the engine, but not driven away, and lamp remains illuminated.

Do the entry level readers work well enough for me to understand the issue, maybe delete the fault? Thinking something like Motopower MP69033 or is something significantly more expensive required?

Hello David,

The ideal would have been to have started it on a fully charged battery and taken it for an ‘Italian tube’ there and then. Simple starting it puts a high current load on the battery, which then dictates a need to recoupe that discharge via. a reasonable run. Then is the time to evaluate what warning lights remain illuminated. 
Regards,

Gareth. 

1 hour ago, David A3 said:

Thanks for the replies. My manual shows it as Emission control system

Battery now fully charged. I’ve started the engine, but not driven away, and lamp remains illuminated.

Do the entry level readers work well enough for me to understand the issue, maybe delete the fault? Thinking something like Motopower MP69033 or is something significantly more expensive required?

I got the same EML light for an oxygen sensor , which was my own fault, as id pulled the fuse fitting a dash cam and didn't put it back in 🥴 .  Which is I suppose emissions related .  Any cheap OBD2 will give you the fault codes ,as most are generic on all cars . 

I took the car for a drive at motorway speeds for about 30mins. Lamp remained on as I return home but after its start-up routine checks next morning, it had disappeared.

I bought a cheap reader and plugged it in this morning. Here’s the screen.

 

Appreciate any thought/comments?

The P0133 code indicates a problem with the oxygen sensor circuit, specifically "O2 Sensor Circuit Slow Response Bank 1 Sensor 1." This code is triggered when the engine control module (ECM) detects that the oxygen sensor's response time is slower than expected. The oxygen sensor measures the oxygen content in the exhaust gases, which helps regulate the air-fuel mixture for optimal engine performance.

Symptoms of P0133

Common symptoms associated with the P0133 code include:

Illuminated check engine light

Decreased fuel efficiency

Rough idling or unstable engine performance

Engine misfires or hesitation during acceleration

Black smoke from the exhaust

Causes of P0133

Several issues can trigger the P0133 code, including:

Faulty oxygen sensor (most common)

Damaged wiring or connectors to the oxygen sensor

Vacuum leaks affecting the air-fuel mixture

Failing mass air flow sensor

Exhaust system leaks

Diagnosis and Repair

To diagnose the P0133 code, a technician typically follows these steps:

Use an OBD-II scanner to confirm the P0133 code and check for related codes.

Inspect the oxygen sensor wiring for damage or corrosion.

Test the oxygen sensor's voltage output to ensure it responds correctly.

Check for vacuum leaks and inspect the fuel system for issues.

Repair options may include replacing the oxygen sensor, repairing wiring, or fixing vacuum leaks. Ignoring this code can lead to poor engine performance and increased emissions.

Thanks @Audisq524 given my lousy duty cycle of late (personal reasons, not my normal driving cycle), relatively short distances, stop start etc, it seems reasonable that the upstream sensor collected a bit of soot and that now, post a 200 mile run, it’s once more clean?

Out of interest, where is the sensor? Is it accessible or does it require half the car to be dismantled to get at it 😩

6 minutes ago, David A3 said:

Thanks @Audisq524 given my lousy duty cycle of late (personal reasons, not my normal driving cycle), relatively short distances, stop start etc, it seems reasonable that the upstream sensor collected a bit of soot and that now, post a 200 mile run, it’s once more clean?

Out of interest, where is the sensor? Is it accessible or does it require half the car to be dismantled to get at it 😩

Afaik 1 is before the cat/dpf the other is after .  Number 1 is or should be up top .  Hopefully someone will know can advise further.