Parts for your 2022 Toyota Aqua-Knock sensor

2022 Toyota Aqua knock sensor — what it does and how to look after it

Based on technical sources, the 2022 Toyota Aqua (MXPK11/MXPK16) with the M15A-FXE 1.5L Dynamic Force hybrid engine is fitted with a knock sensor. Toyota’s Technical Information System repair manual for the M15A-FXE describes the “Knock Control Sensor” and related DTCs P0325, P0327 and P0328, and the Toyota Electronic Parts Catalogue lists the sensor as a serviceable component for this model.

On this Aqua, the knock sensor is a smart little piezoelectric microphone bolted to the engine block. It listens for the high-frequency vibrations that signal detonation (often called “pinging”) and feeds that signal to the engine ECU. When knock is detected, the ECU trims ignition timing and fuelling on the spot to protect pistons and bearings, keep emissions tidy, and get the best out of every litre of petrol. In Aussie and Kiwi conditions—hot days, steep climbs, or a tank of ordinary 91 RON—this real-time control is a quiet hero for engine longevity.

Because the Aqua’s hybrid system starts and stops the engine frequently and can load it up when the battery asks for help, consistent knock control matters. The sensor helps the M15A-FXE run close to the edge of efficiency without crossing into knock, even with the Atkinson cycle and high EGR rates that make the engine super frugal.

There’s no scheduled service interval for the knock sensor, but it deserves attention if any of the following crop up:

• Check engine light with codes P0325, P0327 or P0328
• Noticeable pinging under load, sluggish performance, or worse fuel economy
• Intermittent hesitation after hot restarts

As part of routine servicing, a technician should scan for stored DTCs, visually check the sensor’s connector and engine-earth points, and make sure the engine block area around the sensor isn’t oil-soaked. Electrical contact cleaners and high-pressure washing shouldn’t be used directly on the sensor.

If replacement is needed, it’s a straightforward job for a trained tech. The sensor sits on the cylinder block (typically beneath the intake side). Correct torque and a clean, flat mounting surface are critical—over-tightening or dirt between the sensor and block can cause false readings. Use a genuine or high-quality equivalent sensor, route the harness as per Toyota’s guide to avoid stray vibration or ignition noise, clear any codes, and confirm operation with a road test. There’s no special “calibration”, the ECU adapts automatically once the sensor is fitted correctly.

Where is the knock sensor on a 2022 Toyota Aqua?

It’s mounted to the engine block, typically on the intake side beneath the manifold area. Access is from above with intake components moved aside or from below depending on workshop setup. A pro will follow Toyota’s service procedure to avoid disturbing wiring and to ensure correct torque.

What symptoms show a failing knock sensor on the Aqua?

Common signs include a check engine light with P0325/P0327/P0328, pinging under load, reduced power, and increased fuel use. The ECU often plays it safe by retarding timing, so the car may feel flat rather than noisy. A quick scan and basic checks will confirm it.

Does the knock sensor need routine maintenance?

No regular replacement is scheduled. It’s a monitor-and-react part. During servicing, a scan for codes and a visual check of the connector and harness is enough. Replace only if faulty, damaged, or contaminated, and always to Toyota’s mounting specs to ensure accurate readings.