Parts for your 2020 Ford Fiesta-Knock sensor

2020 Ford Fiesta Knock Sensor

Based on technical sources, the 2020 Ford Fiesta is fitted with a knock sensor and it’s definitely relevant to the car’s engine management. The Ford Service/Workshop Manual for late-model Fiesta (including the 1.0L and 1.5L EcoBoost engines used in 2019–2020) details knock-sensor diagnostics with DTCs such as P0325–P0328, and the Ford Electronic Parts Catalogue (Microcat/EPC) lists a block-mounted knock sensor for these engines. Independent repair data platforms (e.g., Autodata and Haynes) also show a knock-sensor input to the PCM on the Mk8 Fiesta/EcoBoost engines—so it’s there, and it matters.

What does it do? The knock sensor is a small piezoelectric microphone bolted to the engine block. It “listens” for knock (detonation) and tells the ECU to tweak ignition timing and, if needed, boost and fueling. That protects the engine under load, helps it run smoothly across different fuel qualities, and keeps power and efficiency on song—handy when swapping between 91, 95, and 98 RON fuels around Australia and New Zealand. On the Fiesta ST’s 1.5L EcoBoost, it’s a key player in cylinder-specific knock control.

Is it a service item? Not routinely. During regular servicing, a tech should visually check the sensor and harness for damage, oil contamination, or corrosion, and make sure the connector is secure. Good quality fuel and keeping the cooling system healthy both reduce the chance of real knock events, which helps the sensor operate within normal ranges.

• Common signs of trouble: pinging under load, reduced performance, poor fuel economy, and a check-engine light with codes like P0325, P0326, P0327 or P0328.
• Before blaming the sensor: rule out low-octane fuel, intake leaks, carbon build-up, or a misfire.

Replacement tips: the sensor mounts to the cylinder block (typically under the intake side). Disconnect the battery, let the engine cool, and access from above or below depending on model and tools on hand. The mating surface must be clean and dry—no sealants or tape—and the sensor must be tightened to the specified torque so it can “hear” correctly. Don’t twist the harness, route it exactly as from factory to avoid false readings. After replacement, clear any DTCs and allow the ECU to relearn, a short drive cycle with varied load usually does the trick.

There’s no set kilometre interval—replace only if faulty. A healthy knock sensor helps the Fiesta deliver its best performance while safeguarding the engine under the bonnet.

Popular questions

Where is the knock sensor on a 2020 Fiesta (including ST)?
It’s bolted to the engine block on the intake side. Access is generally from the top with the intake plumbing moved aside, or from underneath with the car safely raised. The exact spot can vary slightly by engine (1.0L vs 1.5L EcoBoost), but it’s always block-mounted to “hear” combustion.

Does the knock sensor need regular replacement?
No. It’s not a scheduled service item. Replace it only if diagnostics confirm a fault (e.g., P0325–P0328) and other causes of knock or wiring issues have been ruled out.

What fault codes point to knock-sensor issues on a Fiesta?
Typical codes include P0325 (circuit fault), P0326 (range/performance), P0327 (low input) and P0328 (high input). These can also be triggered by wiring faults, poor connections, or genuine engine knock, so testing is essential before swapping parts.