Parts for your 2019 Toyota Mark x-Camshaft sensor

2019 Toyota Mark X camshaft sensor — what it does and how to look after it

Technical documentation confirms the 2019 Toyota Mark X does use camshaft position sensors. Toyota’s Repair Manual (TIS) for the GRX133 Mark X (SFI and VVT-i sections) lists camshaft position sensors on both banks for the 4GR‑FSE and 2GR‑FSE engines, with ECM signal designations and related DTCs such as P0340 and P0345. The Toyota Electronic Parts Catalog (EPC) for GRX130/133 also shows a “Sensor, Cam Position” fitted on each cylinder bank, and the Toyota Electrical Wiring Diagram (EWD) depicts the CMP sensor circuits to the ECM. So yes—this part is relevant and fitted to the 2019 Mark X.

On the 2019 Mark X, the camshaft sensor helps the ECU know exactly where each cam is, so it can fire the injectors and spark at the right moment and finely control Dual VVT‑i cam timing. That accuracy matters for smooth starts, a steady idle, strong mid‑range pull, good fuel economy, and low emissions. With D‑4S direct injection and chain‑driven cams, these GR‑series V6s rely on clean, precise cam timing data, if a sensor drops out, the ECU can struggle to sync, trigger a Check Engine light, and in some cases fall back to limited performance.

As for servicing, a camshaft sensor isn’t a scheduled replacement item—most live happily for hundreds of thousands of kilometres. The best “maintenance” is regular oil changes with the correct spec, which keeps varnish and debris away from the timing components and sensor faces. If the Mark X throws a cam sensor code (P0340/P0341/P0345/P0346), check the basics under the bonnet first: oil level and condition, the sensor connectors for corrosion or loose pins, and the loom for chafe near the cylinder heads. A scan tool can confirm the CMP/CKP correlation the ECU sees.

• Typical symptoms of a crook cam sensor: long cranking, rough idle, misfire at low revs, sluggish take‑off, higher fuel use, and a CEL.
• When replacing, go quality—genuine or OE‑equivalent. Swap is straightforward: disconnect the battery, remove the engine cover, unplug the sensor on the affected bank, undo the retaining bolt, and pull the sensor straight out. Lightly oil the new O‑ring, seat the sensor squarely, and tighten the bolt to the spec in the Toyota manual.
• After refit, clear codes and road‑test. If faults return, inspect cam timing control (VVT‑i oil control valves) and perform further diagnosis per TIS.

Done right, a fresh camshaft sensor restores crisp starts and keeps the Mark X running sweet as, just the way it should.

Popular questions

Where is the camshaft sensor on a 2019 Toyota Mark X?
It’s mounted at the front of each cylinder head (one per bank on the V6). Pop off the engine cover and you’ll see the small, single‑bolt sensors with a two‑pin or three‑pin plug near the cam sprocket areas.

What are the signs a Mark X camshaft sensor is failing?
Common clues include hard starting, a lumpy idle, hesitant acceleration, poorer fuel economy and a Check Engine light with codes like P0340 or P0345. A scan of live data can confirm erratic or missing cam signals.

Do camshaft sensors need periodic replacement?
Not normally. They’re a fit‑and‑forget item unless there’s a fault. Keep up with oil changes and fix any wiring issues promptly—most failures stem from contamination, heat, or connector problems rather than wear.