Parts for your 2012 Mazda Premacy-Camshaft sensor

2012 Mazda Premacy Camshaft Sensor — Purpose, Fitment and Service Advice

Yes, the 2012 Mazda Premacy (CW, also known as Mazda5 in some markets) uses a camshaft position sensor. This is confirmed by Mazda’s CW-series Workshop Manual (Engine Control System), which details the Camshaft Position (CMP) sensor circuit and diagnostics, and by the Mazda Electronic Parts Catalogue for LF-VE (2.0L) and L5-VE (2.5L) petrol engines listing a CMP sensor in the engine management system. Typical Mazda diagnostic sections also list DTCs P0340/P0341 for CMP faults on these engines, further verifying its presence.

On this model, the camshaft sensor helps the engine computer line up the camshaft’s exact position with the crankshaft. That sync lets the PCM run sequential fuel injection, fire the plugs right on cue, and control variable valve timing smoothly. When it’s healthy, cold starts are crisp, idle is steady, and fuel economy stays tidy. When it’s crook, drivers may notice long cranks, misfires, a flat spot off the mark, or the Check Engine light with those CMP codes popping up.

It’s not a scheduled replacement item in normal servicing, but it is worth a look whenever the rocker cover’s off or if there’s oil weeping around the top of the head. The sensor usually sits at the timing chain end of the cylinder head under the bonnet, exact spot can vary by engine variant. Keeping the connector clean and the wiring loom secure away from heat and sharp edges helps it last the distance. If the rocker cover gasket leaks, oil can wick into the connector, so nipping that leak early prevents grief.

• Common signs it needs attention: hard starting, rough idle, sudden loss of power, increased fuel use, and DTCs P0340/P0341.
• Basic replacement guidance: disconnect the battery negative, unplug the sensor, remove the retaining bolt, swap the O-ring if supplied, refit and torque to the workshop spec (often around 8–10 N·m, check the manual), clear codes and road-test. No programming is typically required, the PCM will relearn on a short drive.
• Cleaning vs replacing: if it’s just light grime or oil on the body or connector, a careful clean and connector repair can sort it. Internal sensor faults or damaged wiring call for a new unit.

For anyone clocking big kilometres or seeing intermittent stumbles with no other cause, a quick CMP inspection under the bonnet can save a lot of head-scratching.

FAQs

Where is the camshaft sensor on a 2012 Mazda Premacy?
It’s mounted on the cylinder head at the timing chain end, near the top of the engine. Access is from above with the engine cover off. Engine variants may place it slightly differently, so checking the CW Workshop Manual or the VIN-specific parts catalogue helps pinpoint it.

What fault codes point to a bad camshaft sensor?
P0340 (Camshaft Position Circuit) and P0341 (Camshaft Position Range/Performance) are the big ones on these Mazdas. You may also see related misfire codes if timing sync is lost. Always rule out wiring damage or oily connectors before condemning the sensor.

Do these cars use one or two camshaft sensors?
Most 2012 Premacy petrol variants use a single CMP sensor. Market and engine differences exist, so some catalogues may show variations. The PCM correlates the cam signal with the crank sensor to run VVT and injection sequencing.