Parts for your 2003 Mitsubishi Pajero-Temperature sensors

2003 Mitsubishi Pajero Temperature Sensors — what they do and how to look after them

Based on Mitsubishi’s NM/NP Pajero Workshop Manual (2002–2006) for Engine Electrical and Automatic Transmission systems, plus common diagnostic procedures outlined for the MUT-III scan tool and mainstream service data (e.g., Autodata/Mitchell), the 2003 Mitsubishi Pajero absolutely uses multiple temperature sensors. These include the engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensing, ambient temperature for climate control, and—on autos—transmission fluid temperature. So yes, temperature sensors are relevant and fitted to this model.

On a 2003 Pajero (petrol V6 and 3.2 Di-D diesel), the ECT sensor is the big one for drivability. It sits in the coolant passage—commonly at the thermostat housing or cylinder head—and tells the ECU how hot the engine is. The ECU then adjusts fuel, ignition, idle speed and fan operation. There’s also IAT measurement in the intake tract (often combined with the MAF on petrols), which helps fine-tune fuelling. Automatic versions monitor ATF temperature to protect the transmission and modify shift behaviour, and the HVAC system uses ambient temperature to keep the cabin comfy.

While these sensors are generally reliable, old age, heat cycles and coolant contamination can make them go out of spec. The result can be hard cold starts, rich running, high fuel use, lazy transmission shifts or the cooling fans staying on too long.

• Service tips: at each coolant change or major service (around 40,000–60,000 km), inspect sensor connectors for corrosion or brittle plastics, verify the harness isn’t rubbing under the bonnet, and scan live data (ECT/IAT/ATF) from cold through to operating temp looking for smooth, believable readings.
• Replacement pointers: only work on a stone-cold engine, catch and reuse or replace coolant as required, and fit a new sealing washer/O-ring. Torque to spec from the workshop manual—over-tightening can crack housings. After refilling coolant, bleed air properly and confirm radiator fans cut in and out at the expected temps with a scan tool.
• Quality matters: stick with OE or a reputable brand so the ECU sees the right resistance curve. If fault codes like P0115–P0119 appear, verify wiring first before condemning the sensor.

Looked after properly, Pajero temperature sensors tend to be fit-and-forget items—just keep an eye on coolant quality and electrical connectors, and they’ll keep the big wagon happy across Aussie and Kiwi kilometres.

Popular questions about 2003 Mitsubishi Pajero temperature sensors

Where is the engine coolant temperature sensor located on a 2003 Pajero?
Typically it’s threaded into the coolant passage near the thermostat housing or on the cylinder head, with a two-pin connector. On some variants there’s a separate single-wire sender for the dash gauge, so don’t mix them up. If unsure, follow the upper radiator hose to the thermostat housing and look for the two-pin sensor.

What are the symptoms of a failing temperature sensor on a Pajero?
Common signs include hard cold starts, high fuel use, rich exhaust smell, cooling fans running constantly or not at all, erratic idle, or an engine light with ECT/IAT codes. Live data that jumps around or doesn’t rise smoothly from cold is a giveaway.

Should the coolant temperature sensor be replaced with the thermostat?
It’s not mandatory, but it’s smart preventative maintenance if the vehicle has high kilometres or there’s evidence of corrosion. If you’re draining the coolant to do a thermostat anyway, the extra labour to swap the sensor is minimal—just use the correct sealing washer and torque spec, then bleed the cooling system properly.