Parts for your 2004 Mitsubishi Pajero-Knock sensor

2004 Mitsubishi Pajero knock sensor — is it fitted and what does it do?

Based on Mitsubishi technical literature, the 2004 Mitsubishi Pajero is fitted with a knock sensor on the petrol V6 variants (6G74 3.5L in some markets and 6G75 3.8L in NP-series), and it is not used on the 3.2L DI‑D diesel (4M41). The Mitsubishi Pajero/Montero 2003–2006 Workshop Manual (Engine—6G7 and Engine Electrical sections) details a “Knock/Detonation Sensor” and related diagnostics (e.g., P0325/P0330) for the petrol V6. The Mitsubishi ASA electronic parts catalogue for NP-series also lists a knock sensor for the 6G7x petrol engines, with no equivalent listing for the 4M41 diesel. Diesels like the 4M41 don’t need a spark-driven knock sensor, their ECU manages combustion via injection timing and pressure using other sensors, and the design does not employ a conventional knock sensor.

For owners of a 2004 Pajero with the petrol V6, the knock sensor is a small, clever microphone bolted to the engine block that listens for detonation (pinging) under the bonnet. When it “hears” knock, it signals the ECU to trim ignition timing and protect the engine. That means smoother running, better fuel economy, and less chance of holed pistons on a hot day or when stuck with ordinary 91 RON fuel out bush.

They’re pretty robust and not a scheduled replacement item, but heat, age and oil contamination can upset them. Typical symptoms of a dodgy sensor or wiring include:

• Check Engine Light with codes like P0325/P0330
• Sluggish performance, especially under load, or unexpected pinging
• Higher fuel use because the ECU plays it safe and retards timing

On the V6, the sensor sits in the valley of the block under the intake manifold, so access is a bit of a spanner job. It’s wise to inspect/replace it when you’re already in there for spark plugs, intake gaskets, or a plenum clean around the 100,000–150,000 km mark. If replacing, use a quality OEM-equivalent sensor, keep the mating surface clean and dry, route the harness away from hot bits, and tighten it to the workshop manual torque spec—correct torque matters for sensitivity. After refit, clear codes and perform an ECU relearn, a short varied drive helps the timing maps settle. If the vehicle regularly pings on 91 RON, consider running 95/98, especially when towing or in high ambient temps.

For the 3.2 DI‑D diesel owners: there’s no knock sensor to service. If you’re hearing diesel clatter or feel performance drop, look to injectors, fuel quality, EGR, boost leaks, or timing control rather than a knock sensor.

Where is the knock sensor on a 2004 Mitsubishi Pajero?

On petrol V6 models, it’s mounted in the V of the engine block under the upper intake manifold, roughly central. There isn’t one on the 3.2 DI‑D diesel.

What fault codes point to a bad knock sensor on a 2004 Pajero?

Common OBD-II codes are P0325 (Knock Sensor 1 circuit) and P0330 (Knock Sensor 2 circuit). Wiring damage, poor connector contact, or incorrect sensor torque can trigger these. The ECU may pull timing, making the vehicle feel doughy.

Can a faulty knock sensor cause poor fuel economy or low power?

Yes. If the ECU can’t trust the signal, it retards timing to protect the engine. That safety net reduces power and can bump up fuel use until the fault is fixed.