Parts for your 2021 Mazda Cx-5-Crank angle sensor

2021 Mazda CX-5 crank-angle-sensor: what it does and how to look after it

Based on Mazda’s KF-series CX-5 workshop manual (Engine Control System), Mazda Australia/New Zealand parts catalogues for the 2021 CX-5, and the factory OBD-II DTC list that includes crankshaft position faults (P0335–P0339) for Skyactiv-G and Skyactiv-D engines, the 2021 Mazda CX-5 is fitted with a crank-angle-sensor (crankshaft position sensor). It’s a core input for the engine control system and very much relevant to this model.

On the 2021 CX-5, the crank-angle-sensor tracks crankshaft speed and position, letting the ECU fire spark and inject fuel at exactly the right time. It also helps coordinate features like variable valve timing and i-Stop. If that signal goes missing or messy, you’ll see hard starting, stalling, rough running, poor fuel economy and a check engine light.

There’s no scheduled replacement for the crank-angle-sensor in Mazda’s service schedule. It’s a fit-and-forget part unless there’s a fault. As part of regular servicing, a sensible approach is to visually inspect the wiring and connector for oil contamination, heat damage or chafing, and make sure any splash shields that protect it are refitted properly after other work. If the engine has had metal debris from a previous failure, ensure the sensor tip area is clean.

When replacement is needed, use a quality OEM-equivalent sensor and a new O-ring if specified. The sensor is mounted low on the engine block (near the crank pulley/flywheel area, depending on engine), typically accessed from underneath after removing the undertray. Standard workshop steps apply: let the engine cool, disconnect the negative battery terminal, unclip the connector, remove the retaining bolt, swap the sensor, lightly lubricate the O-ring, seat it squarely, and tighten to the manufacturer’s torque spec. Route the harness away from moving parts and hot exhaust sections. Clear DTCs, then road test and confirm live data is stable.

No coding is normally required on this model, however, it’s good practice to clear adaptations and perform an idle learn with a scan tool if prompted. Typical labour time is around 0.5–1.0 hour. If you’re chasing intermittent cut-outs or a no-start with P0335/P0336, don’t forget to rule out battery/earth issues and inspect the crank trigger wheel for damage.

• Common symptoms: long crank/no start, sudden stall, misfire at low speed, MIL on
• Owner tip: fix any front crank seal leaks early—oil on the connector can cause drama over time

FAQs

How can someone tell if the crank-angle-sensor is failing on a 2021 Mazda CX-5?
They’ll usually get a check engine light and faults like P0335–P0339. Other giveaways are hard starting (especially warm), random stalling at idle, or a sudden no-start with good fuel pressure and spark issues. A scan tool showing unstable engine speed (RPM) while cranking is another strong hint.

Is it safe to keep driving with a dodgy crank-angle-sensor?
Not really. If it fails outright, the engine can stall or refuse to start, which isn’t ideal in traffic. If it’s only intermittent, it may run but be unreliable. Best bet is to diagnose it promptly and sort it before it leaves anyone stranded.

What does replacement usually cost in Australia or New Zealand?
Ballpark only: parts are often in the $120–$350 AUD/NZD range depending on brand, and labour is commonly 0.5–1.0 hour. All up, many workshops land between $250 and $550 AUD/NZD. Prices vary by engine variant and workshop rates.