Audi P0030

Bank 1 sensor 1 heater circuit fault on Audi TFSI — connector heat damage common on longitudinal engines.

Audi P0030 — Bank 1 sensor 1 heater circuit fault on Audi TFSI — connector heat damage common on longitudinal engines. Typical UK independent garage cost: £100–£340.

What actually causes P0030 on a Audi

A4 B8 2.0 TFSI: the upstream sensor sits inches from the turbo and the four-pin connector melts on cars parked hot. Heater circuit opens intermittently first, then permanently. 3.0 TFSI S4: usually the sensor itself as it's a twin-flow design that stresses the heater element.

Audi engines that log P0030

• 2.0 TFSI EA888 (A4 B8, A5)
• 3.0 TFSI EA837 (S4, S5, Q5)
• 1.4 TFSI EA211 (A1, A3)

How we diagnose P0030 on a Audi

1. VCDS full scan and readiness monitor status
2. Heater resistance at sensor — 3–10Ω cold, open = sensor or connector
3. Inspect connector housing for melt, replace pigtail with OEM repair harness (£45)
4. Bosch OE sensor only, reset readiness monitors after fit

The common misdiagnosis to avoid

Coding out the fault with VCDS — it comes back at next MOT emissions check. Also, don't fit a NTK sensor on 3.0 TFSI; Audi ECM logs P0133 for slow response on non-Bosch parts.

Audi P0030 repair cost in the UK

Expect £100–£340 including parts and labour at an independent garage. Main-dealer quotes on Audi are usually higher for the same job, and the spread exists because the cheap cause and the expensive cause throw the same code — pay for the diagnosis before you pay for parts.

Bob's workshop tip

A4 B8 2.0 TFSI — the OEM pigtail repair harness from Audi is worth every penny. Pattern connectors melt again.

Codes usually seen alongside P0030 on Audi

• P0031
• P0133
• P0135

Symptoms drivers report with P0030

• Engine warning light comes on within 1–3 miles of a cold start every time
• MPG drops 3–6 in short-trip city driving (ECU can't close-loop until the sensor's warm)
• MOT emissions test failure on CO or HC when the tester samples cold
• Sooty smell from the exhaust on start-up, especially on frosty mornings
• No drivability issue — car pulls normally, no misfire, no limp
• Sometimes clears itself after a 30-minute motorway run then returns overnight
• Often paired with P0031 (heater low) or P0032 (heater high) — same sensor circuit

Repairs that clear P0030

• Replace O2 sensor
• Check fuse and wiring

For the generic, all-makes explanation of this code — meaning, every known cause and UK cost bands — see our P0030 guide.

Reading P0030 on a Audi properly

A generic reader will show P0030 and nothing else. What matters is the freeze-frame data stored with it — engine speed, load, coolant temperature and fuel trims at the moment the fault was logged — plus whether any other module on the Audi has logged something at the same time. Codes rarely arrive alone, and the order they were stored in usually points at which one is the cause and which are the consequences.

Clearing P0030 without fixing it

Erasing the code resets the Audi's readiness monitors as well as the light. The fault returns on the next drive cycle if the cause is still there, and in the meantime the incomplete monitors can stop the car passing an emissions check. After a genuine repair, the car is driven until the relevant monitor completes before it is handed back.

Bob's Mechanical Repairs is an independent garage in Birnam, Dunkeld, Perthshire, with 32 years of Bob's experience on the tools. If P0030 is showing on your Audi, bring any scan results with you — we will read the live data ourselves, confirm which cause it actually is, and price the repair before any work starts.