Audi A3 Warning Lights and Dashboard Symbols: What Each Lamp Asks of You, and the A3 Units Behind Them

How does general Audi guidance grade A3 lamps by colour?

With three colours, although not every lamp is given one.

This is general guidance for Audi lamps, not an A3 handbook, though it says the A3 shares its lamps with other modern Audis. Lamps, colours and display messages vary across the 8L (1996–2003), 8P (2003–2013) and 8V (2012–2020) and with specification, so your own A3’s handbook is the final word.

Nothing on this page comes from Audi: Sinspeed is an independent workshop with no connection to Audi or its dealers. The tables keep two voices apart: unlabelled text gives the general guidance, and “Our advice:” introduces ours.

Which red lamps on an A3 mean you should stop?

Most of these are red in the guidance: the oil lamp can be yellow or red, the gearbox lamp is sometimes red, and power steering is red on A3s from 2003, as our steering page records. Four of the six ask you to stop.

Lamp	What it is reporting	Your next move
Brake system (red)	On while you drive, it can mean the brake fluid is low.	Slow down gently, without harsh braking, and stop where it is safe. A garage should check the fluid; if braking feels wrong, call for recovery rather than drive on.
Coolant temperature (red)	Overheating. A leak may have left the coolant low, or a head gasket may have failed.	Stop straight away. Let the engine cool before reading the level on the coolant tank, topping up and looking for leaks; if the lamp comes back, have the cause found.
Engine oil (yellow or red)	The guide gives three possibilities: oil that has overheated, an oil level that is too low, or oil pressure that is too low.	The engine needs to be off, and the car parked somewhere safe, as soon as traffic allows. Look for leaks and check the level, adding oil if it is low; if it was already correct, the oil pump could be the problem, so have the car recovered.
Airbag (red)	Something in the restraint system has a fault, whether an airbag, the sensing that detects a front passenger, or a seat belt pretensioner.	Have it checked immediately. In a crash, a bag might not inflate, or might inflate unexpectedly.
Power steering (red on A3s from 2003)	A power steering fault; the symbol sometimes shows without its exclamation mark. For A3s from 2003, our steering page lists a red steering lamp among the signs of fault 01309.	Steering will be much heavier, which could be dangerous at high motorway speeds. Take extra care, and get it checked as soon as possible.
Gearbox or clutch (sometimes red)	The transmission side has a problem; expect a text message on the display to go with the lamp. The guidance says this lamp can sometimes appear red.	Stop when it is safe to do so, then contact a garage immediately.

Yellow, orange and uncoloured A3 lamps: how urgent is each?

Besides the oil lamp, the guidance colours only two lamps yellow or orange; most fault lamps get no colour, so take that from your dashboard.

Yellow or orange in the guidance

Lamp	What it is reporting	Your next move
EPC (yellow)	Electronic Power Control has a fault and the car is in limp mode, with power cut to limit damage. The accelerator pedal, traction control, cruise control, fuel injection or the engine can be involved.	Get to a garage, or home, at the earliest chance.
Glow plugs, diesel (usually orange)	Like the engine management lamp, it reports a fault with how the engine runs or its emissions. Flashing: the problem has escalated and needs attention sooner.	Book it in with a professional soon, and treat a flashing lamp as needing immediate action.

No colour in the guidance

Green lamps and status symbols: when is an A3 lamp just information?

Green is the only information colour the guidance defines: the system is on or working correctly. Blue and white symbols are not covered there, so check them in your handbook.

Some lamps report a state, not a failure. A flashing ESP lamp shows the system holding grip, and ESP OFF shows it has been turned off. The service lamp is a maintenance reminder. Where pre sense is fitted, its lamp flags a sensor problem, and its safety features are reduced until it is put right.

Brake with ABS, ESP with ABS, steering with others: two A3 lamps at once

Two lamps lit together still leave the failed part unnamed. Only one pairing gets its own advice in the guidance.

• Brake lamp with ABS. This is the pairing the guidance singles out: the braking system has malfunctioned and the brakes may not work properly, and EBD’s lamp can join them. This one ends the journey: park up immediately and arrange recovery.
• ESP with ABS. Nothing in the guidance covers the two together. Taken separately, ABS asks for careful driving and a prompt check, a steady ESP lamp for a garage. Our advice: leave more room until both are checked. See what ESP does and ABS and traction control lights on together.
• On our A3 ABS pages. ABS and ESP warnings are a listed symptom for the A3’s ATE MK70 unit, and the 2012–2020 and 1996–2003 pages list the brake lamp showing with the ABS light. Other causes are named too, so the garage’s codes decide.
• Steering lamp with others. There is no combined entry. Our advice: where instructions differ, follow the stricter one. For the steering lamp, our 01309 page says that with a “No signal/communication” status, the battery, supply, earth and connector are checked before the control unit.

Which A3 units behind the warnings do we repair, by generation?

These facts come from our own A3 repair pages and hold only for the years each names. The lamp alone never names the unit; diagnosis does.

The instrument cluster on 8L, 8P and 2016–2020 A3s

A failing cluster matters twice: it is a fault, and it shows the other warnings. Our Audi A3 and S3 instrument cluster repair page lists a pixelated centre display, needles misreading fuel or temperature, flicker until warm, cut-outs and total power failure.

Each generation has its own emphasis: warning lamps that flicker or stay lit on our 8L page; on the 8P, the whole dash going dead at once, the fault most tied to its cluster; on the 2016–2020 car, warnings that match no real fault. Our pages name fuses, wiring, senders or another control unit as things to rule out first.

A new cluster would need programming to the car, because the cluster is tied to the key coding. Our route keeps the original: your A3’s own cluster is repaired and returned with its mileage and key coding left exactly as they were, under a lifetime warranty. See the Audi A3 (2003–2012) cluster and Audi A3 (2016–2020) cluster repairs, or all our Audi instrument cluster repairs.

Fault 01309 on A3s from 2003: the electric steering rack

Every A3 from 2003 left the factory with an electric power steering rack carrying its motor and the J500 control module. Fault 01309 names that module, with the status “No signal/communication” or “Implausible signal”. Our Audi A3 electric power steering fault 01309 page lists the red steering lamp and assistance that is heavy, cuts in and out, or is heavy one way only.

If diagnosis points at the rack, your garage removes and posts it, and we repair the car’s own rack, control unit included. It refits with no coding; a steering-angle basic setting and alignment are normal fitting steps. The repair carries a lifetime warranty.

The ABS unit, generation by generation

Each of our A3 ABS pages says a faulty unit normally loses ABS while the ordinary brakes keep working, and notes that a lit ABS light fails the MOT.

• 1996–2003, ATE MK20: an ABS lamp that comes on over bumps or in damp weather, then clears, with implausible-signal faults.
• 2003–2013, ATE MK60: a fault stored against the pump, often beside an implausible-signal fault, and a light that will not stay off. See the Audi A3 (2003–2013) ATE MK60 ABS pump.
• ATE MK70 (listed for 2003–2013): a pump running too long or not at all, changed pedal feel under ABS, and ABS and ESP warnings. See the Audi A3 ATE MK70 ABS pump.
• 2012–2020: a diagnostic tool that cannot reach the ABS module, ABS lit with ESP out of action, and codes that will not clear. See the Audi A3 (2012–2020) ABS pump.

Sensors, wiring, connectors and fluid level come first. When it is the unit, your garage posts it and we repair that same one; other Audi units are under Audi ABS pump repairs.

Gearbox warnings: the DSG mechatronic and the S tronic control unit

For the A3 (2003–2013) DSG, our mechatronic page lists a “Gearbox malfunction: you can continue driving” message, a flashing PRNDS display, harsh or jerky changes, limp mode with a gear held and drive dropping out. The mechatronic is the transmission control unit inside the gearbox housing. Low battery voltage, old or low gearbox oil, wiring faults and a worn clutch can cause similar signs.

On the 2017–2020 A3, the S tronic control unit is part of the mechatronic; its page lists shifts that gradually lose smoothness, a “Transmission malfunction” warning, a flashing gear display and limp mode. Once limp mode sets in, on either car, drive only to get home.

Either way, your garage removes the mechatronic and posts it, the gearbox and car staying put; refitting, with any adaptation the gearbox needs, is part of the job. See the Audi A3 (2003–2013) DSG mechatronic and Audi A3 (2017–2020) transmission control unit repairs.

Engine lamps, and the 8P’s K03/K04 turbo

Engine management, EPC, glow plug and DPF lamps start with the codes your garage reads, since none of them singles out one part. If that diagnosis points at the turbo on an 8P (2003–2013), our Audi A3 8P K03/K04 turbocharger page lists power loss or limp mode, exhaust smoke and boost faults, with codes such as P0299 (underboost) and P0234 (overboost).

Airbag lamps and no-starts

The airbag lamp needs diagnosis first, as several parts of the restraint system can set it. If the codes point at the control unit, that is a part we repair. Tell us its part number and we will confirm; the range is listed under our airbag control unit repairs. For an A3 that will not start, see how to tell if a no-start is the immobiliser.

Only the part travels. The car stays with your garage throughout: they remove the unit their diagnosis points to, send it to our Epsom workshop and fit it again when it comes back, coding or adaptation included. Testing happens on our in-house Hardware-in-the-Loop rigs, which simulate real-world heat, vibration and load.

Five questions about Audi A3 warning lights