Parts for your 2019 Toyota Mark x-Knock sensor

2019 Toyota Mark X knock sensor — fitment, purpose and service advice

Based on technical sources, the 2019 Toyota Mark X (GRX130/GRX133, 4GR‑FSE 2.5L and 2GR‑FSE 3.5L V6) is fitted with knock sensors. Toyota’s Repair Manual for the Mark X (Engine Control – SFI System, 4GR‑FSE/2GR‑FSE) specifies piezoelectric knock sensors used for ignition timing control, and the Toyota Electrical Wiring Diagram (GRX130/133) shows two knock sensor circuits to the ECM (one per bank). These documents, alongside DENSO’s knock sensing design notes and Toyota’s OBD fault code set (P0327–P0334), confirm the part is integral to this model’s engine management.

On the 2019 Mark X, the knock sensor listens for high-frequency vibration that points to detonation (knock). The ECM uses that signal to trim ignition timing in real time, keeping the V6 smooth, efficient and safe under Aussie and Kiwi conditions, especially with our varied fuel qualities and hot summer runs. With the high-compression, direct‑injection GR engines, accurate knock control is a big deal for performance, economy, and longevity.

There’s no scheduled replacement for the knock sensor in normal servicing of a 2019‑Toyota‑Mark‑X knock‑sensor, but it pays to keep an eye on tell‑tales. If the sensor or its wiring plays up, expect a check engine light, sluggish performance, higher fuel use, or pinging under load. Scan tools usually flag codes like P0327/P0328 (Bank 1) or P0332/P0333 (Bank 2).

When replacement is needed, expect intake manifold removal to access the sensors in the V of the block. Sensible workshop practice goes a long way: disconnect the battery, use new intake gaskets, route the loom exactly as per the clips, and install an OEM‑quality sensor onto a clean, dry, flat seat—no sealants or tapes. Tighten to the factory torque and angle so the piezo element reads vibrations correctly. After refit, clear codes and let the ECU relearn with a varied drive cycle. Given age and access effort, many techs replace both banks together if one has failed.

For ongoing peace of mind, run the recommended octane petrol, keep the cooling system healthy, and fix any oil or coolant leaks that could weep into the valley. During routine services, a quick visual for harness damage and a scan for pending DTCs is cheap insurance for the Mark X’s smooth V6.

• Fitted: Two knock sensors (Bank 1 and Bank 2), piezoelectric type, ECU‑monitored.
• Typical faults: Stored DTCs, reduced power, detonation noise, poor economy.
• Service tip: Replace with quality parts, correct torque, and proper loom routing.

Popular questions about 2019 Toyota Mark X knock sensors

Does the 2019 Mark X have one or two knock sensors?
It uses two—one per cylinder bank on the V6. Toyota’s GRX130/133 wiring diagram and the repair manual show separate Bank 1 and Bank 2 knock sensor circuits feeding the ECM. That lets the ECU fine‑tune timing per bank for clean power and protection.

Is it safe to drive with a knock sensor fault?
The car will usually pull timing to protect the engine, so it may feel down on power and drink a bit more fuel. If the knock sensor can’t report properly and real knock occurs, there’s a risk of engine damage. Best to book it in promptly rather than push on for weeks.

What’s involved in replacement and how long does it take?
Access is under the intake manifold in the engine’s valley. A technician will remove the intake, fit new gaskets, install the sensor to a clean seat with the specified torque, clip the harness correctly, then clear codes and road test. Workshop time typically ranges from around two to three hours depending on tooling and model specifics.