Parts for your 1996 Mitsubishi Pajero-Knock sensor

1996 Mitsubishi Pajero knock sensor: which models have it, what it does, and how to look after it

Based on factory documentation and EPC listings, a knock sensor is fitted to 1996 Mitsubishi Pajero petrol V6 models (6G72 3.0L and 6G74 3.5L), and not used on the diesel models (4M40 2.8L and 4D56 2.5L). Technical references include the Mitsubishi Pajero/Montero Factory Service Manual (1996–1998) ignition/engine control diagnostics showing knock sensor circuit checks and DTC P0325, the Mitsubishi ASA/CAPS electronic parts catalogue which lists a “Sensor, knock (detonation)” for 6G7x engines (market-dependent part numbers such as MD335220/MD152999), and the 4M40 diesel engine workshop manual, which contains no knock sensor in its engine electrical layout. Diesels control combustion via injection timing and don’t rely on spark-based detonation control, so they don’t use a knock sensor on this model year.

For petrol V6 Pajeros of this era, the knock sensor is a quiet hero. It listens for high-frequency vibration (detonation) and tells the ECU to trim ignition timing just enough to protect the engine while keeping power on tap. On the 6G72/6G74 it’s typically mounted in the V of the block under the upper intake plenum, so it’s out of sight but central to keeping the motor happy on Aussie and Kiwi fuel blends.

Owners chasing a rough idle, flat spots up hills, or higher-than-usual fuel use may find the ECU has pulled timing because the sensor is unhappy. Common fault codes include P0325 (knock sensor circuit). Some DOHC 6G74 variants in certain markets use two sensors, but most 1996 Pajeros run a single unit.

Replacement is straightforward but fiddly due to access. Expect to remove the upper intake to reach the sensor and loom. Key tips:

• Use an OEM-quality sensor, cheap copies often have the wrong frequency response.
• Install on a clean, dry boss, don’t use sealant or Teflon on the threads.
• Tighten to the specified torque (typically around 20–25 N·m, confirm in your workshop manual) to ensure proper sensitivity without crushing the piezo element.
• Inspect and replace brittle wiring and clips, heat under the plenum can harden the harness.

As part of regular servicing, it’s worth checking the connector for corrosion, ensuring the harness isn’t chafing, and keeping the cooling system and PCV in good nick—excess heat and oil vapour can invite carbon buildup and knock. Running the recommended octane for your V6 helps the sensor do less work and keeps timing where it belongs.

If yours is a diesel 4M40/4D56, there’s no knock sensor to worry about. Combustion is managed by injection timing and boost control, and detonation sensing like a petrol spark-ignition engine isn’t required, which is why the diesel wiring diagrams and parts listings omit a knock sensor entirely.

• How can I tell if my 1996 Pajero actually has a knock sensor?
  If it’s a petrol V6 (6G72/6G74), yes. If it’s a diesel (4M40/4D56), no. Check your engine code on the build plate, or scan for P0325—this code is associated with petrol knock sensors.
• Where is the knock sensor on the V6?
  It’s mounted on the top of the block in the valley under the upper intake plenum. You’ll generally need to pull the plenum for access.
• Is it safe to drive with a bad knock sensor?
  The ECU will usually play it safe by retarding timing, so you’ll notice less grunt and higher fuel use. Short trips at light throttle are unlikely to hurt, but it’s best to sort it promptly to avoid potential engine stress under load.