Parts for your 2001 Mitsubishi Pajero-Map sensor

2001 Mitsubishi Pajero MAP sensor: what’s fitted and how to look after it

Based on factory and industry references, a MAP (Manifold Absolute Pressure) sensor is fitted to the 2001 Pajero when equipped with the 3.2 DI‑D turbo‑diesel (engine code 4M41), where it’s used as a boost/manifold pressure sensor. See: Mitsubishi Pajero/Montero NM–NP Workshop Manual (Engine 4M41 DI‑D, Intake/Airflow Control and DTC diagnostics), Mitsubishi ASA electronic parts catalogue (Intake/Boost pressure sensor listings for 4M41), and Gregory’s Pajero/Montero 1997–2009 service manual (engine management overview). For the 3.5 V6 petrol (6G74) sold in Australia/NZ, engine load is measured primarily by a MAF sensor and an atmospheric pressure input, so a traditional MAP sensor on the manifold isn’t used, which is why you won’t find one on many local petrol NM models.

On the 3.2 DI‑D, the MAP sensor’s job is to tell the ECU exactly how much pressure is in the intake manifold, so it can juggle fuel, EGR and turbo boost without drama. It helps keep the diesel smooth off idle, tidy on economy, and gutsy when towing. Because the 4M41 runs boost, the ECU really leans on that pressure signal to avoid over‑ or under‑boost conditions and to meet emissions targets.

Servicing-wise, the MAP sensor doesn’t have a fixed replacement interval, but it does appreciate a clean environment. Soot and oil mist can build up in the sensor port and the little passage in the manifold. As part of a big service or if the vehicle’s been doing lots of short trips or dusty work, it’s worth a check.

• Symptoms of a lazy MAP: flat spots, smoky exhaust, rough idle, higher fuel use, limp‑home under load, or boost‑related fault codes.
• Basic care: with the battery off, unplug the connector, remove the sensor carefully, and clean only the port with appropriate electronics‑safe cleaner. Don’t poke the sensing element.
• Refit with the proper seal, a perished O‑ring can cause leaks and dodgy readings. Torque to spec per the workshop manual, not “feel”.
• If faults persist, verify the hose/manifold port isn’t blocked and check wiring continuity back to the ECU before condemning the sensor.

Replacement is straightforward: use a quality sensor matched to the 4M41. Clear codes, then take it for a decent drive cycle so the ECU can relearn. Pair MAP checks with a fresh air filter and an EGR/intake inspection, there’s no point fitting a new sensor to a manifold choked with soot. Look after it and the Pajero will happily clock the kilometres, whether it’s the school run or a long haul with the caravan.

FAQs

Where is the MAP sensor on a 2001 Pajero 3.2 DI‑D?
It’s mounted on or near the intake manifold plenum on the passenger side of the bay (RHD), reading manifold pressure via a small port. You’ll see a two‑ or three‑bolt flange and an electrical connector. Some versions use a short passage or hose into the manifold—make sure that passage isn’t blocked with soot.

What are common MAP sensor failure signs on the 4M41?
Sluggish acceleration, black smoke, erratic idle, higher fuel use, and boost‑related DTCs are typical. Before replacing, rule out split intercooler hoses, a clogged air filter, or intake/EGR deposits, as these can mimic a dud MAP reading.

Does the 3.5 V6 petrol Pajero have a MAP sensor?
Most AU/NZ‑delivered 3.5 V6 MPI models use a MAF‑based strategy and don’t have a traditional manifold‑mounted MAP sensor. Load is calculated from measured airflow and barometric input per the petrol section of the NM workshop manual.