Parts for your 2017 Toyota Mark x-Knock sensor

2017 Toyota Mark X knock sensor — what it does and when to sort it

Technical sources confirm the 2017 Toyota Mark X (GRX130 series, 4GR-FSE 2.5L and 2GR-FSE 3.5L V6) is fitted with knock sensors. Toyota’s factory Repair Manual for the GRX130 platform details “Knock Control Sensor” operation within the engine control system, and the Toyota Electronic Parts Catalogue lists two sensors (one per bank) for these V6 engines. Typical OBD-II fault codes applicable to this model include P0325/P0327/P0328 (Bank 1) and P0330/P0332/P0333 (Bank 2), all pointing to knock sensor circuits. So yes — this Mark X uses knock sensors, and they’re an essential part of how the ECU keeps the engine happy on Aussie and Kiwi fuels.

The knock sensor’s job is simple but critical: it listens for combustion knock (pinging) and tells the ECU to trim ignition timing before anything gets unhappy. That means smoother running, better fuel economy, and protection for pistons and valves under load or hot conditions. On the Mark X’s GR-series V6, the sensors sit in the valley beneath the intake manifold, bolted to the block to “hear” the engine clearly.

They’re not a routine service item, but they’re worth a look-in during major services. A few smart habits help:

• Use the recommended octane (95 RON or as specified) to reduce knock events.
• Keep connectors and looms tidy, heat and vibration can fatigue wiring in the V.
• Scan for codes if a Check Engine light appears, rough running develops, or there’s pinging under load.

If replacement is needed, it’s a manifold-off job on these V6s. That makes it a good time to refresh intake gaskets and inspect the loom. Use a quality OE-spec sensor, fit it to the clean block face, and tighten to the torque spec in the Toyota Repair Manual — over-tightening can skew readings, under-tightening can cause false signals. Route the harness exactly as per the manual to avoid rub-through. After refitting, clear codes, perform an ECU relearn if required, and road test under varying loads.

Common signs of a dodgy knock sensor on a 2017 Mark X include:

• Check Engine light with P0325–P0334 codes
• Sluggish performance or poor fuel economy
• Audible pinging on hills or when towing

Look after the basics — clean connections, correct fuel, and proper installation — and the Mark X’s knock control will quietly get on with keeping the V6 smooth and safe for many kilometres.

FAQs: 2017 Toyota Mark X knock sensor

Where is the knock sensor on a 2017 Mark X?
On the GR-series V6, there are two sensors mounted to the engine block in the valley under the intake manifold — one for each bank. Access generally requires removing the manifold, so inspection and replacement are best done alongside other intake-side work.

Can it be driven with a faulty knock sensor?
The ECU will usually pull timing to protect the engine, so it may run flat and drink more fuel. Continuing to drive risks masking real knock, so it’s best to scan, confirm the fault, and sort wiring or replace the sensor promptly.

Should both knock sensors be replaced at the same time?
If one has failed due to age or heat, many workshops recommend replacing both while the intake is off. It saves labour later and ensures consistent signal quality across both banks.