Parts for your 1999 Mitsubishi Pajero-Map sensor

1999 Mitsubishi Pajero MAP sensor — is it used, and what does it do?

Based on factory and trade references, a MAP (manifold absolute pressure) sensor is relevant to the 1999 Mitsubishi Pajero. The Mitsubishi Pajero Service Manual (1997–2002 volumes) lists a “Manifold Absolute Pressure/Boost Pressure Sensor” as an ECU input on the 2.8L 4M40 and 3.2L 4M41 diesels, where it manages boost and fuelling. The petrol 6G72/6G74 engines are documented with a Kármán vortex MAF as the primary load sensor, and certain calibrations include a manifold pressure sensor for EGR monitoring, altitude compensation and plausibility checks. Trade databases such as Autodata and Bosch ESI also show a MAP/boost sensor on the diesel variants and, market-dependent, a MAP on some petrol models. So, if the ’99 Pajero is a turbo‑diesel, it definitely runs a MAP/boost sensor, many petrols may also have one, though the MAF is the main airflow input.

On vehicles fitted with it, the MAP sensor’s job is to report the absolute pressure in the intake manifold so the ECU can calculate engine load. That lets the ECU fine‑tune fuelling and ignition (petrol) or injection timing and quantity (diesel), adjust boost control, and compensate for altitude. On turbo‑diesels like the 4M40/4M41, the MAP effectively doubles as a boost sensor, helping prevent overboost and limp‑mode dramas.

It’s not a scheduled replacement item, but it pays to give it some love during servicing. Keep the intake tract clean, check the sensor’s electrical connector for corrosion, and inspect any vacuum/boost hose leading to a remote‑mounted sensor for splits or oil contamination. If cleaning is needed, only use electronics‑safe cleaner, no wire brushes, no poking, and definitely no oily sprays. After cleaning or replacement, clear fault codes, perform any idle/ECU relearn if applicable, and confirm readings on a scan tool. Key‑on/engine‑off should read close to local barometric pressure (around 101 kPa at sea level), and values should climb smoothly with throttle or boost.

• Common symptoms of a dodgy MAP: sluggish performance, black smoke (diesel), rough idle, poor fuel economy, hard starts, or limp mode.
• Typical DTCs: P0105, P0106, P0107, P0108, and over/under‑boost codes on diesels.
• When replacing, stick to OEM‑spec parts and ensure the sealing grommet or hose is fresh and tight.

Plenty of 1999 Pajeros live long, happy lives with their original MAP sensor. A quick check at each service—especially on turbo‑diesels exposed to soot and oil mist—is cheap insurance against on‑road headaches.

Popular questions about 1999 Mitsubishi Pajero MAP sensors

Where is the MAP sensor on a 1999 Pajero?
On the 4M40/4M41 turbo‑diesels it’s usually on or near the intake manifold or intercooler piping, sensing boost/manifold pressure through a short hose or direct port. Petrol models that have one tend to mount it on the manifold or firewall with a small vacuum hose. If the engine uses a MAF as the primary sensor, the MAP may be present only on certain trims or markets.

Can you clean a MAP sensor, or should you just replace it?
Light contamination can be carefully cleaned using electronics‑safe cleaner. Avoid contact cleaners that leave residue, and don’t poke the sensing port. If it still reads incorrectly or throws repeat DTCs after cleaning and checks of hoses/connectors, replacement is the go. Always verify operation with live data after the job.

What fault codes point to a bad MAP sensor on a ’99 Pajero?
Look for P0105–P0108 (circuit range/performance, low, or high). On diesels, you may also see overboost/underboost or limp‑mode events tied to implausible MAP readings. Rule out split hoses, clogged ports, and connector issues before condemning the sensor.