Parts for your 2020 Toyota C-hr-Knock sensor

2020 Toyota C‑HR knock sensor — what it does and how to look after it

Yes, the 2020 Toyota C‑HR is fitted with a knock sensor. This applies to both the 2.0‑litre petrol and the 1.8‑litre hybrid variants used in AU/NZ markets. Technical sources that confirm its use include the Toyota Service Information (TIS) Repair Manual for C‑HR (which provides diagnostic steps for DTCs P0327/P0333 “Knock Sensor Circuit”), Toyota’s Electronic Parts Catalogue (EPC) listing a knock sensor sub‑assembly for 2020 C‑HR engines, and professional databases such as Autodata/ALLDATA that publish factory knock‑sensor testing procedures for this model.

The knock sensor is a small piezoelectric microphone bolted to the engine block beneath the intake manifold. Its job is to listen for pinging (detonation) and tell the ECU to gently dial back ignition timing when needed. That lets the C‑HR run smoothly on everyday Aussie and Kiwi fuels, protects the engine under load or on hot days, and keeps economy on track over long kilometres.

It’s not a routine service item, but it does benefit from a bit of care. During servicing, a tech will usually check for stored knock‑sensor fault codes, make sure the engine earths are healthy, and eyeball the sensor harness for heat damage or oil contamination. If the check engine light pops up with P0327 or P0333, common culprits are a loose or incorrectly torqued sensor, a damaged connector, or wiring rubbed through on the block. Because mounting torque and orientation affect how the sensor “hears” the engine, it must be installed exactly to the workshop manual — no guessing with the spanner and no thread sealant on the mating face.

Replacement is straightforward but fiddly due to access: the air box/throttle body or intake runners may need to come off. Best practice is to disconnect the battery, work on a cool engine, route the loom in the original clips, and clear codes with a scan tool afterwards. A short road test lets the ECU relearn knock control. Symptoms of a crook knock sensor or circuit include the MIL on, a noticeable drop in power (the ECU plays it safe and retards timing), rough running under load, and higher fuel use. Left too long, it won’t usually grenade the engine, but it will make the C‑HR feel a bit doughy — so it’s worth sorting sooner rather than later.

• Tech tip: use quality fuel and keep the cooling system healthy, both reduce real knock and keep the sensor from working overtime.
• If the manifold’s off for other work (plugs, injectors), it’s a good time to inspect the sensor and loom.

Where is the knock sensor on a 2020 Toyota C‑HR?

It’s mounted on the engine block beneath the intake manifold, roughly mid‑block. Access is usually from the top after removing the air intake gear, some techs approach from underneath depending on tools and variant. Always let the engine cool before reaching in.

Does the knock sensor need routine replacement?

No. It’s not a scheduled service item. Replace it only if it’s faulty, damaged, contaminated with oil/coolant, or if diagnostics confirm a sensor or wiring issue. Signs include a check engine light with P0327/P0333, reduced performance, and pinging under load.

Is it safe to drive with a faulty knock sensor?

The C‑HR will usually default to safer, retarded ignition timing, so it’ll run but feel flat and use more fuel. Short trips to a workshop are typically fine, but it’s best to fix it promptly to restore proper performance and detonation protection.