Parts for your 2007 Toyota Mark x-Camshaft sensor

2007 Toyota Mark X camshaft sensor — purpose, servicing and replacement

Technical sources confirm the 2007 Toyota Mark X is fitted with camshaft position sensors and they’re absolutely relevant to its operation. Toyota’s Repair Manual for the GRX120/121 Mark X (3GR‑FSE and 4GR‑FSE engines) specifies Camshaft Position Sensors “G1/G2” on each cylinder bank, the Electrical Wiring Diagram shows G and NE (crank) signals used by the ECM, and Toyota’s Electronic Parts Catalogue lists camshaft sensor assemblies for GRX120/121 models. So yes — the Mark X uses cam sensors as standard hardware.

On the 2007 Mark X’s GR‑series V6, the camshaft sensor lets the engine computer know exactly where each cam is in relation to the crank. That timing info is critical for quick starts, smooth idle, sequential fuel injection, precise spark, and the Dual VVT‑i system. If the signal goes missing or erratic, the car can be hard to start, feel flat under load, or light the MIL with codes like P0340–P0349. Under the bonnet, there’s one sensor per bank (two total), mounted near the ends of the camshafts.

There’s no scheduled replacement interval — they’re solid‑state and generally reliable — but they do benefit from attention during routine servicing of a 2007‑Toyota‑Mark‑X camshaft-sensor. Good practice includes:

• Inspecting the connectors and loom for oil contamination, brittle insulation, or loose clips.
• Checking for rocker cover oil leaks wicking into the plug.
• Scanning live data for clean cam/crank correlation and no dropouts.

Replacement is straightforward: disconnect the battery, unplug the sensor, remove the retaining bolt, and gently twist the sensor free. Always fit a quality OEM‑equivalent sensor, renew the O‑ring, and lightly oil it before install. No programming is required, after refitting, clear any codes and take a short drive so the ECM can relearn trims. On the rear (firewall) bank, access can be tighter — allow extra time and use care not to damage nearby harnesses.

Common hints something’s up include:

• Long cranking or intermittent stalling once warm
• Rough idle, poor fuel economy, or sluggish response
• Stored DTCs P0340–P0349 and related VVT‑i performance codes

If a new sensor doesn’t sort persistent cam correlation faults, it’s worth checking timing chain stretch, VVT‑i actuator performance, and engine earths. Kept clean and dry, the Mark X’s cam sensors typically clock up plenty of kilometres without fuss.

Popular questions

Does the 2007 Mark X have more than one camshaft sensor?
Yes. The GR‑series V6 in the 2007 Mark X uses one camshaft position sensor per cylinder bank (two total). Toyota documentation labels them G1 and G2, and the ECM compares both against the crank sensor for accurate timing and VVT‑i control.

Do you need to program the ECU after replacing a camshaft sensor?
No special programming is required. Fit the new sensor with a fresh O‑ring, clear any fault codes, and road‑test. The ECM will adapt normally, if a code returns, recheck connectors, wiring, and mechanical timing.

Where are the camshaft sensors located on a 2007 Mark X?
They’re mounted on the cylinder heads near the cam ends. Bank 1 (front) is relatively easy to reach, Bank 2 sits closer to the firewall and may need more careful access under the engine cover and adjacent plumbing.