Parts for your 1995 Mitsubishi Pajero-Oxygen sensor

1995 Mitsubishi Pajero Oxygen Sensor

Technical references confirm that a 1995 Mitsubishi Pajero may or may not use an oxygen sensor, depending on the engine. The Mitsubishi Pajero NH–NJ Workshop Manual (Fuel and Emission Control sections) and Mitsubishi ASA parts catalogue indicate that petrol EFI variants (notably the 3.0 L 6G72 V6) use a heated oxygen sensor (HO2S) for closed‑loop fuel control. Bosch sensor application guides list a 4‑wire heated sensor for the same petrol models. For the 2.5 L 4D56 and 2.8 L 4M40 diesels of this era, these sources show no oxygen sensor fitted, as those engines use mechanical/early electronic diesel injection without closed‑loop lambda control.

For petrol‑powered 1995 Pajeros, the oxygen sensor is a small but crucial bit of kit. Sitting in the exhaust stream, it measures leftover oxygen so the ECU can tweak fuelling on the fly. That keeps the air‑fuel mix on the money, saving fuel, smoothing drivability, and protecting the catalytic converter. When the sensor gets tired, the ECU loses that fine control and the Pajero can start drinking more petrol, feel a bit doughy off the mark, and throw a check‑engine light.

As part of regular servicing, it’s smart to give the O2 sensor a once‑over. Look for damaged wiring, heat‑baked insulation, or a cracked body. Don’t try to clean the sensing tip—solvents and wire brushes will ruin it. If it’s coming out for replacement, use a proper O2‑sensor socket, apply a small amount of sensor‑safe anti‑seize to the threads if the new unit doesn’t come pre‑coated, and tighten to the spec in the workshop manual. After fitting, clear any codes and verify closed‑loop operation and fuel trims with a scan tool once it’s at operating temp.

• Common signs it’s on the way out: increased fuel use, rough idle, hesitation, black soot at the tailpipe, failed emissions, and a stored fault code (often a slow response or heater circuit fault).
• Typical service life is around 160,000 km, but age, oil or coolant contamination, and silicone sealants can shorten it. Many owners choose a proactive replacement around that mark to keep the cat happy and the wallet healthier.

Diesel owners take note: for 1995 diesel Pajeros (4D56/4M40), an oxygen sensor isn’t used. Those engines don’t run petrol‑style closed‑loop control, fuelling is handled by the injection pump and related sensors, so there’s no lambda probe to service.

FAQs

Where is the oxygen sensor on a 1995 Mitsubishi Pajero 3.0 V6?
On the petrol 6G72, the primary heated O2 sensor is threaded into the exhaust near the manifold/downpipe area so it sees hot gases quickly. Access is from under the vehicle, a slotted O2‑sensor socket helps get around the wiring.

How often should the O2 sensor be replaced?
There’s no hard‑and‑fast interval from Mitsubishi, but many sensors are done by about 160,000 km. If fuel economy drops, the check‑engine light appears, or diagnostics show lazy response or heater faults, replace it rather than trying to clean it.

Can a bad oxygen sensor damage the catalytic converter?
Yes. A lazy or failed sensor can make the engine run rich, overheating and poisoning the cat. Fixing a dodgy sensor early is far cheaper than replacing a cooked catalytic converter.