Parts for your 2020 Mazda 3-Camshaft sensor

2020 Mazda 3 Camshaft Sensor — What It Does and When to Replace It

Yes, the 2020 Mazda 3 is fitted with a camshaft position sensor. This is confirmed by Mazda’s BP-series Workshop Manual (Engine Control System, Camshaft Position [CMP] Sensor), Mazda’s Electronic Parts Catalogue for the BP Mazda 3 range, and Mazda’s published OBD-II DTC list that includes P0340/P0341 for the camshaft sensor circuit on 2019–2021 BP models. So, the camshaft sensor is absolutely relevant to this vehicle.

On the 2020 Mazda 3 (Skyactiv-G and Skyactiv-X engines), the camshaft sensor tracks the camshaft’s position relative to the crankshaft. The engine control module uses that info to run sequential fuel injection, fire the spark at the right time, and command variable valve timing. It also helps tidy up cold starts, stabilise idle, and keep fuel economy on point. If the sensor goes out of whack, the car can be hard to start, feel doughy off the line, or throw a check engine light.

There’s no set maintenance interval for the camshaft sensor, but it benefits from a quick look whenever the rocker cover area is open during servicing. Keep connectors clean and clipped firmly, and check the harness routing so it’s not rubbing on anything hot or sharp. Fresh oil at the proper spec also helps the variable valve timing system behave, which reduces the chance of timing correlation faults that can be mistaken for a bad sensor.

Replacement is a straightforward job for a tech. The sensor is mounted at the cylinder head, remove the electrical connector, undo the retaining bolt, and slide the sensor out. A light smear of clean engine oil on the new O-ring helps it seat properly. After refit, clear any fault codes, start the engine, and confirm smooth idle and normal operation of systems like i‑Stop. Most BP models don’t require coding for a new sensor, though a crank/cam correlation check with a scan tool is good practice.

• Common symptoms: long crank/no start, rough idle, hesitation, higher fuel use, start/stop disabled, and DTCs P0340/P0341.
• Tips: use quality parts, don’t pinch the O-ring, and inspect wiring and connectors for heat or oil damage.

Where is the camshaft sensor on a 2020 Mazda 3?

It’s mounted on the cylinder head at the timing chain end. Exact spot varies slightly by engine variant, but it’s typically at the front/right of the bay (as you face the car). Access is usually straightforward with basic hand tools.

Can you drive with a faulty camshaft sensor?

You might be able to, but it’s not a great idea. Expect hard starting, random stalling, limp-home behaviour, or poor fuel economy. It can leave the driver stranded if it deteriorates, so get it diagnosed and sorted promptly.

Does the camshaft sensor need programming after replacement?

Generally, no. The Mazda 3’s ECU will use the new sensor without coding. Clear any codes, then road test. Some workshops perform a crank/cam relearn with a scan tool as a belt-and-braces step.