Parts for your 2001 Mitsubishi Lancer-Temperature sensors

2001 Mitsubishi Lancer temperature sensors: what they do, where they are, and when to replace them

Technical sources confirm temperature sensors are absolutely used on the 2001 Mitsubishi Lancer. The Mitsubishi workshop manual for the 2001 CE/CG series details an Engine Coolant Temperature (ECT) sensor for the engine control unit and, on many variants, a separate single‑wire sender for the dash gauge. Haynes service manuals for Lancer models of this era also describe both ECT and Intake Air Temperature (IAT) sensing, with the IAT often integrated into the mass air flow (MAF) unit. OBD‑II standards and fault codes (e.g., P0115–P0119 for ECT) further support their presence and function on this vehicle.

On a 2001 Lancer, temperature sensors quietly keep the show running. The ECT sensor feeds the ECU accurate engine temperature so it can sort cold starts, fuel delivery, ignition timing, idle speed, and radiator fan operation. An IAT sensor helps the ECU fine‑tune fueling based on incoming air temperature. Many cars of this era also run a separate one‑pin sender purely for the dash gauge, so drivers see a stable needle even while the ECU reads a more dynamic signal.

When looked after, these sensors rarely need scheduled replacement. As part of regular servicing, it’s smart to inspect the sensor connectors, look for coolant seepage around the ECT, and keep coolant fresh and correct to spec—contaminated coolant can corrode sensors and threads. If faults do crop up, scanning live data is gold: a stone‑cold engine showing 90°C, or a fully warm engine reading freezing temps, points squarely at the ECT or its wiring.

• Common signs of a dodgy ECT: hard cold starts, rough idle when warm, rich running and excessive fuel use, radiator fans stuck on or never coming on, and a wandering temp gauge (if separate sender is failing).
• Basic replacement tips: let the engine cool, relieve pressure, disconnect the plug, drain a little coolant, swap the sensor and sealing washer/O‑ring, then refill and bleed the system. Tighten to factory spec—over‑zealous spanner work can crack housings.
• Testing guides in the workshop manual list resistance‑versus‑temperature checks, many ECT sensors read higher resistance when cold and lower when hot. If wiring integrity and grounds check out but readings stay off, replacement is straightforward and affordable.

For Aussie and Kiwi Lancers—whether 1.5, 1.6, 1.8 or early 2.0—the temperature sensors are a small outlay that protects engines from poor running and overheating headaches.

Popular questions

Where is the coolant temperature sensor on a 2001 Lancer?
On most 2001 Lancers, the ECT is threaded into the thermostat housing or cylinder head near the upper radiator hose. Some variants also have a separate single‑pin sender for the dash gauge nearby. Access is usually from the top of the engine bay.

What symptoms point to a failing temperature sensor?
Expect rich running, rough idle when warm, hard cold starts, unexpected radiator fan behaviour, or a check‑engine light with codes like P0115–P0119. Fuel economy can slide, and the dash gauge may act strangely if the separate sender is on the way out.

Do 2001 Lancers have an IAT sensor as well?
Yes. Most 2001 Lancers use an Intake Air Temperature sensor, often built into the MAF unit. It helps the ECU trim fueling for hot or cold intake air, improving drivability and emissions.