Parts for your 2017 Lexus Is-Knock sensor

2017 Lexus IS knock sensor — purpose, fitment and servicing advice

Factory technical sources confirm the 2017 Lexus IS does use knock sensors. Lexus repair manual procedures for the 2.0‑litre turbo 8AR‑FTS and 3.5‑litre V6 2GR‑FKS/FSE include diagnostics for knock control sensor circuits (e.g., DTCs P0325, P0327, P0330), and the Toyota/Lexus Electronic Parts Catalogue lists the knock sensor(s) for these engines. That makes the knock sensor relevant and fitted across the 2017 IS range.

The knock sensor is a piezoelectric “microphone” that listens for the high‑frequency vibration caused by detonation (knock). When knock is detected, the ECU trims ignition timing and, on the 8AR‑FTS, may also moderate boost. That protects the engine while keeping it smooth and efficient on Aussie and Kiwi 95/98 RON petrol. If the sensor or its wiring plays up, the ECU switches to a conservative map, which can feel a bit lazy and use more fuel, and it will turn on the check engine light.

• Check engine lamp with codes like P0325/P0327/P0330
• Rattling or pinging under load
• Sluggish performance and poorer economy
• Rough running when hot

It isn’t a scheduled service item, but it’s worth checking the harness and connectors under the bonnet during routine services, especially for heat‑hardening, oil or coolant contamination, or a loose mounting. Correct fuel octane, a healthy cooling system, and keeping carbon build‑up in check all help the sensor and ECU keep the tune spot‑on.

If replacement is needed, use quality OEM‑spec parts, clean the mating surface, and tighten exactly to the factory torque, over‑ or under‑torque changes sensitivity. On the 8AR‑FTS there’s typically a single sensor on the block, on the V6 there are two in the V‑bank under the intake, so access takes longer. Typical steps are battery disconnect, intake and bracket removal for access, sensor swap, reassemble, clear codes, then road‑test under load. Many techs allow about 1.0–2.5 hours depending on engine and access. It’s smart to check for any service bulletins, confirm power/ground/signal integrity with a multimeter or scope, and rule out wiring faults before condemning the sensor.

Popular questions about the 2017 Lexus IS knock sensor

How many knock sensors are on a 2017 Lexus IS?
The 2.0‑litre turbo 8AR‑FTS generally uses one knock sensor on the block. The 3.5‑litre V6 (2GR‑FKS/FSE) typically uses two non‑resonant knock sensors mounted in the engine’s V. Exact fitment can be confirmed by VIN in the parts catalogue.

What are the common fault codes for a bad knock sensor on this model?
Common Lexus/Toyota codes include P0325 (Knock Sensor Circuit), P0327 (Knock Sensor Low Input) and P0330 (Knock Sensor 2 Circuit). Drivers might also notice pinging under load, reduced power, or higher fuel use alongside the MIL.

Is it safe to drive with a faulty knock sensor?
The car will usually run with reduced performance as the ECU retards timing to protect the engine. Short trips may be manageable, but it’s not wise to delay repairs—if real knock isn’t being measured correctly, there’s a risk of engine damage. Book it in and get it sorted promptly.