Parts for your 2018 Toyota Mark x-Camshaft sensor

2018 Toyota Mark X Camshaft Sensor

Based on Toyota service literature (Toyota Global TIS Repair Manual for GRX13# series), the Electrical Wiring Diagram for the Mark X (2016–2019), and the Toyota Electronic Parts Catalogue for the 4GR-FSE/2GR-FSE engines, the 2018 Toyota Mark X is fitted with camshaft position sensors. The documents list “Camshaft Position Sensor (G signal)” for both banks of the V6, diagnostic DTCs such as P0340/P0345, and inspection procedures, confirming the part is both relevant and used on this model.

The camshaft sensor on a 2018 Toyota Mark X plays a key role in how smoothly the V6 runs. On the 4GR-FSE and 2GR-FSE engines, it feeds the ECU exact cam angle data so the car can time fuel injection and spark properly, and command Dual VVT-i on the intake and exhaust. Paired with the crank sensor, it lets the ECU run true sequential injection under D-4S and keep cold starts clean, idle steady, and power delivery strong across the rev range.

There isn’t a set service interval for the cam sensor itself, but it definitely deserves attention if drivability goes off. Typical signs it’s time to check or replace include:

• Hard starting, rough idle, or a flat spot under load
• Check engine light with codes like P0340/P0345
• Poor fuel economy or the engine dropping into limp mode

Good oil and filter changes help the sensor live a long life, because clean oil supports the VVT actuators that rely on the same timing feedback. During routine servicing, it’s worth a quick look under the bonnet to make sure the sensor connectors are seated, the wiring isn’t chafed, and there’s no oil weeping from the sensor O-ring.

Replacement on a Mark X is typically straightforward: remove the engine cover, unplug the sensor on the front of the cylinder head, undo the retaining bolt, and ease the sensor out. Lightly oil a new O-ring, seat the new unit squarely, nip the bolt to spec, reconnect, clear any codes, and take it for a road test. Most workshops will book about 0.5–1.0 hour per sensor. Sticking with a genuine or high-quality aftermarket part avoids odd starting behaviour or repeat faults.

If the car shows intermittent faults, a technician should also scope the cam and crank signals and check grounds. Many “sensor faults” trace back to a tired connector or damaged loom rather than the sensor element itself.

Where is the camshaft sensor on a 2018 Mark X?

On the GR-series V6 in the Mark X, camshaft sensors are mounted at the front of each cylinder head near the timing cover. They read a target on the camshaft to report position back to the ECU. Access is usually under the plastic engine cover.

What symptoms point to a failing camshaft sensor?

Owners often notice hard starts, uneven idle, misfires at low revs, lack of go, and the check engine light. Scan tools frequently show codes like P0340 or P0345. Because VVT timing depends on this signal, the engine may feel lazy or go into limp mode.

Does the 2018 Mark X have more than one camshaft sensor?

Yes. The V6 layout uses a camshaft position sensor for each bank. If a fault code specifies Bank 1 or Bank 2, it helps pinpoint which side needs attention, but wiring checks should still be done before replacing parts.