Parts for your 2006 Subaru Impreza-Temperature sensors

2006 Subaru Impreza Temperature Sensors

Based on the 2006MY Subaru Impreza Factory Service Manual (Engine Diagnostics and Wiring sections), Subaru Technical Information System diagrams, and well-regarded service texts such as the Haynes Subaru Impreza manual (2002–2011) and Autodata, temperature sensors are absolutely fitted and relevant on the 2006 Subaru Impreza. These include the engine coolant temperature (ECT) sensor, intake air temperature (IAT) sensing (often integrated into the MAF on turbo models), ambient temperature input for HVAC, and—on automatic models—automatic transmission fluid temperature monitoring.

On a 2006 Subaru Impreza, the temperature sensors are the quiet achievers that keep things sweet under the bonnet. The ECT sensor is the real workhorse: it tells the engine computer how warm the engine is so it can sort out cold-start enrichment, ignition timing, idle speed control, radiator fan operation, and air-con load decisions. The IAT input helps the ECU fine-tune fuelling by accounting for air density, while ambient temperature influences climate control behaviour. Auto transmissions also rely on fluid temperature to protect the gearbox and adjust shift strategies.

There’s no routine replacement interval for the ECT sensor, but it’s smart to check it during regular servicing. Look for corroded or loose connectors, coolant seepage around the sensor body, cracked wiring insulation, or a wobbly temperature gauge. Typical fault signs include hard cold starts, poor fuel economy, rich running, the radiator fans stuck on, or a check-engine light with codes like P0115–P0119. A quick scan with an OBD-II tool comparing the live coolant temp to a cold ambient reading is a handy sanity check.

When replacing the ECT sensor, only work on a cold engine. Depressurise the cooling system, disconnect the two-pin plug, and remove the sensor with an appropriate deep socket. Fit a quality OEM-equivalent sensor, if a sealing washer or pre-applied sealant is supplied, use it as directed. Tighten to service manual torque (around 18–22 N·m, confirm for the specific engine variant), reconnect the plug, and bleed the cooling system properly to avoid air locks. Top up with the correct Subaru-approved coolant mix. A smear of dielectric grease on the connector helps keep moisture at bay. For IAT issues on models with the sensor integrated in the MAF, replacement usually means swapping the MAF assembly—diagnose carefully before committing.

• Common symptoms: rough cold starts, erratic idle, poor economy, fans running constantly, temp gauge misbehaviour, CEL with P0115–P0119.
• Service tip: sensor faults are often electrical—always check wiring and grounds before replacing parts.

Popular questions

Where is the coolant temperature sensor on a 2006 Impreza?

On EJ25 engines it’s typically threaded into the coolant crossover near the front/top of the engine, close to the thermostat housing area and under/near the intake manifold. Access varies by model, some need the intake ducting or covers removed for a clear shot. Always identify the two-pin ECT plug before removal.

Can you drive with a bad temperature sensor?

It’ll often still run, but it’s not wise. The ECU may default to rich fuelling or force the fans on, which can mask real overheating or waste fuel. Drivability can suffer and long-term engine wear or catalytic converter damage can result. Sort it sooner rather than later.

Does the 2006 Impreza have more than one temperature sensor?

Yes. There’s the engine coolant temperature sensor, intake air temperature sensing (often inside the MAF on turbo models), outside/ambient temperature for HVAC, and an ATF temperature sensor on automatic transmissions. Each serves a different control system.