Parts for your 2020 Mazda 3-Crank angle sensor

2020 Mazda 3 crank angle sensor (crankshaft position sensor): purpose, care and replacement

The 2020 Mazda 3 is fitted with a crank angle sensor — more commonly called the crankshaft position (CKP) sensor. Mazda’s BP-series Mazda3 workshop manual lists the CKP as a primary powertrain control input, and the Mazda Electronic Parts Catalogue includes a dedicated CKP sensor for 2019–2021 BP models. It’s fundamental to starting, smooth running and emissions control, and it’s monitored by the PCM with fault codes such as P0335/P0336.

What does it do? The CKP sensor reads a toothed wheel on the crankshaft and tells the PCM the exact crank angle and engine speed in real time. That live data lets the PCM time spark and fuel precisely, coordinate with the cam sensors for variable valve timing, manage stop‑start operation, and detect misfires. Without a clean CKP signal, the engine may crank without firing, stumble, or cut out unexpectedly.

Servicing-wise, the crank angle sensor isn’t a routine replacement item, but it does benefit from a quick inspection when the vehicle is on a hoist. The sensor is mounted to the engine block and “looks” at the crank’s tone wheel, access is typically from underneath the car. Check the connector for corrosion or a loose fit, look for oil weeping that could contaminate the tip, and make sure the harness isn’t rubbing on anything under the bonnet.

If replacement is needed, go for a quality OEM-spec part and a fresh O‑ring. Disconnect the battery, keep the sensor tip clean, and seat it squarely — the air gap is fixed by design, so no shimming or filing. Clear any stored DTCs and verify a stable RPM signal in scan data on the road test. Most BP Mazda3s don’t require programming for a new CKP, the PCM generally self-adapts, but follow the workshop manual steps and perform an idle relearn if needed.

• Typical symptoms of a failing CKP: intermittent no-start, long crank, rough idle, sudden stall, tachometer drop-outs, poor fuel economy, or the MIL flashing with misfire codes.
• Helpful checks before condemning the sensor: battery health and grounds, connector pin tension, harness chafing near the front/rear of the engine, and actual CKP signal quality in live data.
• When in doubt, a scope trace or professional diagnosis beats guesswork — it protects coils, injectors and the catalytic converter from collateral damage.

Technical references: Mazda BP Mazda3 Workshop Manual (Powertrain Control System, Crankshaft Position (CKP) Sensor) and Mazda Electronic Parts Catalogue for BP-series models listing the CKP sensor and associated harness.

Popular questions

Where is the crank angle (CKP) sensor on a 2020 Mazda 3?
It’s bolted to the engine block, aligned to read a toothed wheel on the crankshaft. Access is usually from underneath with the splash shield removed. Exact viewing angle varies with engine and market spec, but if following the harness from the lower front/side of the engine, it’s hard to miss.

What fault codes point to a CKP issue on a 2020 Mazda 3?
Common CKP-related DTCs include P0335 (CKP circuit) and P0336 (CKP range/performance). You may also see misfire codes (P0300–P0304) if the CKP signal is dropping out. Always check battery voltage, connectors and wiring before replacing parts.

Does a new CKP sensor need programming?
Generally, no. The BP Mazda3’s PCM usually recognises a correct CKP signal without special programming. Clear codes, ensure a stable idle, and complete an idle relearn if the manual calls for it. Some scan tools offer a CKP learn function, use it if prompted.