Parts for your 2018 Honda Accord-Knock sensor

2018 Honda Accord knock sensor — what it does and how to look after it

Yes, the 2018 Honda Accord uses a knock sensor. Honda’s 2018 Accord workshop manual (PGM‑FI/ECM section) documents a block‑mounted knock sensor and defines DTCs P0325–P0328 for knock sensor performance and circuit faults. Honda’s OEM parts catalogue likewise lists a “Sensor Assy., Knock” for the 1.5‑litre VTEC Turbo (L15BE), the 2.0‑litre VTEC Turbo (K20C4), and the 2.0‑litre hybrid engine, confirming it’s fitted across the range.

On this Accord, the knock sensor acts like a sensitive microphone bolted to the engine block, listening for the high‑frequency vibration that comes with detonation (pinging). The ECM uses that signal to trim ignition timing and, on the turbo models, manage boost, so the engine runs as far advanced as safely possible. That helps deliver smooth performance, better fuel economy, and protects pistons and bearings from knock damage, even with different petrol qualities found around Australia and New Zealand.

It isn’t a scheduled service item, but it plays a continuous, critical role. If the sensor or its wiring goes out of spec, the ECM will pull timing as a safeguard. Owners may notice the check engine light and reduced performance, along with stored codes such as P0325, P0326, P0327 or P0328 in scan data. Because the sensor lives on the block under the intake side, it also copes with heat, vibration, and the odd oil mist — all reasons to give it a quick look whenever intake or spark plug work is underway.

• When replacement is warranted: confirmed fault codes, persistent pinging under load, sluggishness with no other cause, or visible harness damage.
• Good practice: use a quality OEM‑spec sensor, inspect and route the harness away from hard edges, and keep connectors clean and dry.
• Fitting notes: disconnect the battery, access the sensor from the intake side of the block, and tighten to the factory torque using a torque wrench to avoid false readings. Clear codes and road‑test under load while monitoring knock retard and fuel trims.
• Prevention helps: correct‑octane petrol, healthy cooling, and up‑to‑date ECU calibrations reduce knock activity and keep the sensor working within its comfort zone.

For local conditions, many owners opt for 95–98 RON in the turbo models to minimise knock under hot weather and heavy loads, which lets the ECM lean on the knock sensor less and keep timing optimised.

FAQs

Does the 2018 Honda Accord have a knock sensor and where is it located?
It does. Technical service information and the OEM parts catalogue show a knock sensor fitted to all 2018 Accord engines. It’s threaded into the engine block on the intake side, typically around cylinders two to three, beneath the intake manifold area.

What are common signs of a failing knock sensor on this model?
A check engine light with codes P0325–P0328, noticeable loss of power (especially under load), poorer fuel economy, and occasional pinging. The ECM will usually retard timing to protect the engine, which feels like the car is holding back.

Is the knock sensor a routine maintenance item?
No. It’s replaced on condition. During services that involve intake or ignition work, it’s smart to inspect the sensor and harness, ensure correct routing, and check for oil contamination. If replacement is needed, follow the factory torque spec and procedures.