Parts for your 2015 Audi Q5-Knock sensor

2015 Audi Q5 knock sensor — what it does, whether it’s fitted, and how to look after it

Based on Audi’s ElsaWin/erWin workshop information for the 2015 Q5 (8R) and Volkswagen Group Self‑Study Programmes covering the EA888 TFSI and 3.0 TFSI engines, the petrol variants are equipped with two block‑mounted knock sensors (commonly identified as G61 and G66). Audi’s ETKA parts catalogue also lists knock sensors for these petrol engine codes in the 2015 Q5. By contrast, the 2.0 TDI and 3.0 TDI diesel variants don’t use conventional knock sensors for ignition control, their ECUs manage combustion via injection timing, boost and pressure sensing, so a “knock sensor” isn’t a service item on those engines. That means the knock sensor is relevant and used on 2015 Q5 petrol models.

On a petrol 2015 Audi Q5, the knock sensor’s job is to listen for high‑frequency vibrations caused by detonation (pinging). The ECU uses that signal to trim ignition timing cylinder‑by‑cylinder so the engine can run with maximum spark advance without risking damage. It’s one of the quiet heroes that helps the TFSI pull cleanly on our hot Aussie and Kiwi days, even on variable fuel quality.

There’s no scheduled replacement interval for the knock sensor, they’re replaced on condition. Typical signs it needs attention include a Check Engine Light with codes like P0325/P0330, persistent pinging under load, dull performance because the ECU is pulling timing, and poorer fuel economy. Before condemning the sensor, it’s worth checking basics such as correct‑spec fuel, carbon build‑up, vacuum leaks, and wiring/connector integrity.

• Location: Typically bolted to the cylinder block under the intake side, with two sensors covering pairs of cylinders.
• Fitting tips: The mating surface must be clean and dry, don’t use grease. The sensor must be torqued precisely (often around 20 Nm, but always confirm the spec for the exact engine code in the workshop manual). Incorrect torque can make the ECU “deaf” or overly sensitive.
• Wiring: Route the loom as per factory clips to avoid induced noise. Keep oil and coolant away from the connector.

When replacing, use genuine‑quality parts so the frequency response matches what the ECU expects. After installation, clear fault codes and road‑test under load so the ECU can relearn knock correction. If the car still pings or logs a fault, further diagnosis (scope‑testing the sensor signal, checking engine mounts and intake leaks) is smart. Look after it and the TFSI will reward with smoother, stronger pulls and better fuel economy.

FAQs

Does a 2015 Audi Q5 have a knock sensor?
Yes on petrol (TFSI) models — they use two knock sensors to manage ignition timing. Diesel (TDI) versions don’t use a conventional knock sensor for combustion control, so it isn’t a service part on those engines.

Where is the knock sensor on a 2015 Q5 2.0 TFSI and what’s the torque?
Both sensors are mounted to the side of the engine block beneath the intake manifold area. Typical torque is around 20 Nm, but always verify the exact figure in the Audi workshop manual for your engine code to ensure correct sensitivity.

Is it safe to drive with a knock sensor fault?
The ECU will usually pull timing to protect the engine, so it may feel flat and thirsty. Light local driving to a workshop is generally fine, but continued heavy load or towing isn’t wise until it’s diagnosed and fixed.