Parts for your 2007 Mazda Cx-9-Camshaft sensor

2007 Mazda CX-9 Camshaft Sensor — What it does and when to replace it

Yes, the 2007 Mazda CX-9 is fitted with camshaft position sensor(s). This isn’t guesswork — Mazda’s Workshop Manual for the CX-9 (2007) details CMP sensor inspection and DTCs in the Engine Control System section, the Electrical Troubleshooting Manual lists faults like P0340/P0344 tied to the cam sensor circuits, and the Mazda Electronic Parts Catalogue for the 2007 CX-9 lists a “Sensor, Camshaft Position” for the MZI V6. The Ford-derived MZI 3.5L V6 used in the 2007 model relies on these sensors for variable valve timing and sequential fuel injection.

On this CX-9, the camshaft sensor’s job is to tell the PCM exactly where the camshafts are so it can time fuel injection and spark properly and drive the variable valve timing. Without a clean signal, the engine can hard-start, run rough, feel flat off the line, or throw the check engine light. Typical fault codes include P0340, P0341, P0344 and related VVT codes.

It’s not a routine replacement item, but it is smart to check it during servicing, especially on higher‑kilometre cars. A quick visual of the connectors and loom routing, plus a scan for stored or pending DTCs, helps pick up issues early. Oil seeping from the rocker cover can wick into the plug and disturb the signal, so keeping leaks sorted goes a long way.

When replacement is needed, it’s a straightforward job for a tech. The MZI V6 uses one cam sensor per cylinder bank near the front of each cylinder head, close to the VVT hardware. Fit quality parts, seat the O-ring cleanly, and tighten the retaining bolt to workshop spec (around 8–10 N·m — verify in the manual). Reconnect the plug securely, clear codes, and road test while watching live data for cam/crank synchronisation. If codes return, dig deeper for timing chain stretch, tired VVT solenoids, or wiring faults rather than throwing more sensors at it.

• Common symptoms: hard starting, intermittent stalling, rough idle, poor fuel economy, sluggish response, MIL on with P0340/P0344.
• Quick tips: fix oil leaks that contaminate connectors, avoid mixing up bank 1/bank 2 plugs, and keep harnesses clipped away from heat.
• Good practice: after any cam sensor work, perform an adaptive drive cycle and re-scan to confirm no pending faults.

Popular questions about the 2007 Mazda CX-9 camshaft sensor

Where is the camshaft sensor on a 2007 CX-9?
The MZI V6 has one sensor on each cylinder bank, mounted near the front of the cylinder head and close to the variable valve timing gear. On a transverse layout, one is easier to see at the radiator side, the other sits toward the firewall and can be trickier to reach.

Can you drive with a bad camshaft sensor?
It might still run, but it can be hard to start, lack power, or stall unexpectedly. It can also log further faults and may go into a reduced‑performance mode. For safety and to avoid collateral issues, it’s best to get it diagnosed and sorted sooner rather than later.

Should both cam sensors be replaced at the same time?
Not strictly necessary. Replace the one that’s faulty after proper diagnosis. That said, on high‑kilometre vehicles where access is similar for both banks, some owners choose to do both proactively to save future labour. Always confirm root cause before parts swapping.