Parts for your 1997 Mitsubishi Pajero-Temperature sensors

1997 Mitsubishi Pajero temperature sensors — what they do and how to look after them

Based on the Mitsubishi Pajero/Montero 1991–1999 Factory Service Manual (Engine Electrical, Cooling, and A/T sections), the Mitsubishi ASA electronic parts catalogue, and common reference manuals from Haynes/Gregory’s, the 1997 Pajero is fitted with multiple temperature sensors. These include an Engine Coolant Temperature (ECT) sensor for the ECU, a separate sender for the dash gauge, an Intake Air Temperature (IAT) sensor on petrol models, and an Automatic Transmission Fluid (ATF) temperature sensor on autos. So temperature-sensors are absolutely relevant and used on a 1997 Mitsubishi Pajero.

On this Pajero, the ECT is the big player. It tells the ECU how warm the engine is, so fuelling, ignition timing, idle speed, and on 4M40 diesels the glow plug strategy, all behave properly from frosty starts to beach runs. The dash gauge sender is usually separate, so a dead gauge doesn’t always mean the ECU’s ECT is crook (and vice versa). Petrol models also use an IAT sensor to fine‑tune mixture and timing as the intake charge heats up or cools down. If it’s an automatic, the transmission control uses ATF temperature to manage shift feel and protect the box when things get hot. Some trims with climate control also monitor cabin or ambient temperature to keep the air-con comfy.

When temp sensors drift or fail, the Pajero can run rich, idle high, feel doughy, kick the cold-start strategy at the wrong time, or throw the fuel bill through the roof. Typical red flags include:

• Hard cold starts, rough running, or black smoke (diesel)
• Poor fuel economy, high idle, or rich exhaust smell (petrol)
• Erratic temp gauge versus scan data
• Transmission holding gears too long or going into limp when hot (auto)

Servicing advice for 1997-mitsubishi-pajero temperature-sensors: they’re not routine “replace at X km” items, but they’re worth checking whenever the cooling system is serviced or a drivability niggle pops up. Use a scan tool that speaks Mitsubishi MUT/OBD to compare live coolant temp with the gauge. Inspect connectors for green crusties, brittle wiring, oil or coolant wicking, and poor earths. For the ECT, expect it near the thermostat housing, replace with a quality sensor and new seal, engine cold, after relieving pressure. Catch a litre or so of coolant, swap the sensor, snug to manufacturer spec, then refill with the correct premix and bleed air by running the engine with the heater on hot. For IAT, make sure the airbox/duct is sealed and the sensor is clean. For autos, clean ATF and a healthy cooler keep the internal temp sensor happy, replacement of the ATF sensor generally means pan/valve body work—best left to a transmission specialist.

Stick with reputable parts and don’t cheap out—dodgy sensors can read “a bit off” and waste fuel without ever logging a fault.

Popular questions

What are the symptoms of a bad coolant temperature sensor on a 1997 Pajero?

A crook ECT can cause hard cold starts, rich running, high idle, poor economy, and the cooling fans or glow plug timing behaving oddly. The check engine light may appear, but not always. Comparing scan tool coolant temp against actual warm‑up feel is a quick sanity check.

Where is the coolant temperature sensor located?

On most 1997 Pajero engines it’s threaded into or near the thermostat housing on the intake side of the engine. There’s often a separate sender nearby for the dash gauge, so make sure you’re testing or replacing the ECU’s ECT, not the gauge sender.

Does a 1997 Pajero have more than one temperature sensor?

Yes. Typically there’s an ECU ECT sensor, a separate dash gauge sender, an IAT on petrol models, and an ATF temperature sensor on autos. Climate-control models may add cabin/ambient sensors. Each has a different job, so diagnosis should target the right one.