Parts for your 2016 Toyota Mark x-Knock sensor

2016 Toyota Mark X knock sensor — fitted, what it does, and service tips

Based on Toyota’s technical literature, the 2016 Toyota Mark X (GRX130 series) is fitted with knock sensors. The Toyota Mark X GRX130 Repair Manual (Engine/Hybrid System – SFI System) documents diagnostics for DTCs P0325 and P0330 (Knock Sensor Circuit Bank 1/Bank 2), and the New Car Features (NCF) for the GR series confirms piezoelectric knock sensors are used to control ignition timing under knock conditions. Toyota’s Electronic Parts Catalogue for GRX130 also lists knock sensors and the related sub‑harness. Taken together, these sources show the knock sensor is absolutely relevant and present on the 2016 Mark X, whether equipped with the 4GR‑FSE 2.5L or 2GR‑FSE 3.5L V6.

The GR‑series V6 in the 2016 Mark X uses two piezoelectric knock sensors mounted in the V of the cylinder block (one per bank). The engine control module uses their signals to fine‑tune spark timing, safeguarding performance and the engine itself.

The knock sensor on a 2016 Toyota Mark X plays a quiet but crucial role. It “listens” for detonation (knock) and feeds that info to the ECU so timing can be trimmed on the fly. That lets the V6 deliver crisp power on decent fuel while protecting pistons, bearings, and the head gasket when conditions get a bit harsh—think hot days, heavy loads, or questionable fuel. It’s especially important on the direct‑injected GR engines, which run high compression and lean strategies at times.

It’s not a routine replacement item, but it deserves attention during servicing. On this V6 the sensors sit under the intake manifold in the engine valley, so access needs the upper intake off. When the intake is off for other work (carbon clean, coolant crossover, PCV, or injector seals), it’s smart to inspect both knock sensors and their sub‑harness. Look for brittle wiring, oil or coolant contamination, and green crust on the connectors. Any damage or corrosion can skew the signal and trigger a Check Engine Light with codes like P0325/P0330, flat performance, or poor fuel economy.

• Common signs of trouble: MIL on with P0325/P0330, rattly “ping” under load, lazy acceleration, higher fuel use.
• Service tips: Always follow the factory tightening torque and orientation—clamping force changes sensor sensitivity. Replace aged sub‑harnesses, use quality (genuine or OEM‑equivalent) sensors, and avoid the old “tap the block” test as it can mislead diagnostics.
• Fuel note: The Mark X is specified for premium unleaded in Japan. While the ECU and knock control can adapt, sticking to the recommended RON helps keep timing optimal and knock events low.

If one bank faults, many technicians replace both sensors while the intake is off to avoid a repeat visit. A proper scan‑tool diagnosis, live data review, and a careful visual inspection often saves guesswork. Get the sealing faces clean, route the loom as per the manual, and the GR V6 will be happy for many kilometres.

Popular questions about 2016‑Toyota‑Mark‑X knock sensors

Where are the knock sensors located on a 2016 Mark X?
The GR‑series V6 uses two knock sensors mounted to the cylinder block in the V under the intake manifold—one for each bank. Access requires removing the upper intake, so they’re not visible from above with everything assembled.

Can the Mark X run on 91 if it has knock sensors?
The ECU can trim timing when it detects knock, and the engine will generally cope. However, the Mark X was specified for premium unleaded in its home market. Using the recommended octane helps retain performance and efficiency and reduces how often the knock system has to pull timing.

What does replacement usually involve and cost?
Replacement involves removing the intake manifold, inspecting or replacing the sub‑harness, fitting new sensors with the correct torque and orientation, then clearing codes and road‑testing. Parts are typically mid‑range in price, and labour is the bigger share due to intake removal. Many workshops quote a few hours and often suggest replacing both sensors while in there.