Parts for your 2016 Mazda Cx-9-Camshaft sensor

2016 Mazda CX-9 Camshaft Sensor — Purpose, Care, and When to Replace

Technical sources confirm the 2016 Mazda CX-9 (Skyactiv-G 2.5T, PY-VPTS) uses camshaft position sensors. The Mazda Workshop Manual for the CX-9 (Engine Control System, CMP Sensor section) and the model’s Electrical Wiring Diagram identify CMP sensors on the intake and exhaust cams to support Dual S-VT. Mazda’s diagnostics list DTCs such as P0340 and P0365 for CMP circuits, and genuine/aftermarket parts catalogues list replacement CMP sensors for this vehicle.

On this CX-9, the camshaft sensor (CMP) tells the engine control module exactly where each cam is, so it can fire the injectors and coils in the right order and precisely control valve timing. That means easier cold starts, smoother idle, stronger mid-range torque, and lower fuel use. With Dual S-VT, the ECU constantly checks cam position against the crank to keep the timing on point, and the CMP is the sensor that makes that possible.

There’s no scheduled service interval for the CMP—it’s a sealed, solid-state sensor—but it pays to keep an eye on basic things during routine servicing. Under the bonnet, check the CMP connectors for oil contamination or brittle wiring (rocker cover seepage can wick into plugs). If the Check Engine light pops on with slow cranking, rough idle, misfires, or sudden loss of power, scan for codes like P0340 (cam ‘A’/intake) or P0365 (cam ‘B’/exhaust).

Replacement isn’t a big drama for a competent home mechanic, but most owners will prefer a workshop. Typical steps are:

• Disconnect the negative battery terminal.
• Unplug the CMP connector and remove the small retaining bolt.
• Withdraw the sensor, swap the O-ring, lightly oil it, and refit.
• Route the loom correctly, reconnect, clear codes, and confirm live data and cam/crank sync.

Always use a quality, OE-equivalent sensor and a fresh O-ring, cheap units can give flaky signals and bring the light back on. There’s no special programming required, though a scan tool reset and an idle relearn may be recommended. Good oil quality helps too—clean oil keeps the cam phasers happy, which reduces the workload on the sensor and the ECU’s corrections.

For CX-9 owners clocking big kilometres, a quick visual check of the CMP wiring at each service, and a scan if the idle feels off, is a simple way to stay ahead of issues.

Popular questions

Does the 2016 Mazda CX-9 have one or two camshaft sensors?
Yes—this model uses two: one on the intake cam and one on the exhaust cam. The pair lets the ECU control Dual S-VT accurately and keep fuel and spark timing properly synchronised.

Do camshaft sensors need regular servicing?
No scheduled servicing is required. They’re solid-state units. During routine maintenance, it’s smart to inspect connectors and wiring, especially if there’s any oil mist under the rocker cover. Replace only if faults or related DTCs are present.

Will a faulty camshaft sensor damage the engine?
Direct damage is unlikely, but a failing sensor can cause hard starts, misfires, poor economy, and limp mode. Left unchecked, repeated misfires may stress the catalytic converter. Sorting it early avoids collateral costs.