Parts for your 2000 Nissan Serena-Temperature sensors

2000 Nissan Serena Temperature Sensors — What They Do and How to Look After Them

Temperature sensors are absolutely fitted and relevant on the 2000 Nissan Serena (C24). This is documented in the Nissan Serena C24 Factory Service Manual (EC – Engine Control and HAC – Heater & Air Conditioner sections), which describes the Engine Coolant Temperature (ECT) sensor as a key ECM input and details additional temperature sensing for the climate control system. Nissan’s FAST Electronic Parts Catalogue for the C24 further lists coolant and intake temperature sensing across petrol engines (QR20DE/SR20DE) and diesels of the era, and workshop data sets such as Autodata/Bosch ESI identify the ECT sensor and an intake air temperature (often integrated into the MAF on these Nissans) as standard. So yes — temperature sensors are part of the Serena’s normal operation.

On this model, the ECT sensor screws into the engine’s coolant passage (typically near the thermostat housing). It tells the ECM how hot the engine is so it can sort out cold starts, fuel delivery, ignition timing and when to switch the radiator fans. It also has a say in the dash gauge reading. Many Serenas also rely on intake air temperature for fuelling trim, plus ambient/evaporator temp sensors in the HVAC to keep the cabin comfy, and auto transmissions may monitor fluid temperature for shift quality.

Looking after these sensors is straightforward. During regular servicing, a quick scan-tool check of live data when the engine’s cold should show coolant temperature close to ambient, if it reads wildly off, the ECT or its wiring may be crook. Keep coolant fresh using the correct spec — old or contaminated coolant can cause corrosion at the sensor tip and connectors.

• Common ECT fault symptoms: hard cold starts, rich running, rough idle, poor fuel economy, radiator fan running at odd times, erratic gauge, and check engine light (codes like P0115–P0119).
• Replacement tips: only work on a cold engine, relieve any pressure, catch and reuse/replace coolant as needed, swap the sensor and its sealing washer/O-ring, then bleed the cooling system per the FSM. Don’t use thread tape unless the manual specifically calls for it.
• Afterwards: clear fault codes, verify no leaks, and recheck live data as it warms up, fans should cycle normally once at temperature.

Done right, a faulty ECT sensor swap is a tidy DIY job, otherwise, a trusted workshop can sort it quickly with the proper test gear.

Popular questions about 2000 Nissan Serena temperature sensors

Where is the coolant temperature sensor located on a 2000 Serena?
On most C24 engines it’s threaded into the coolant passage near the thermostat housing, facing the front or side of the head. It has a two-pin connector. Access varies a bit between QR20DE and SR20DE, but it’s generally reachable from the top with the air intake duct out of the way.

Can a temperature sensor be cleaned, or does it need replacement?
If the sensor’s electrically out of spec or the internal thermistor has failed, replacement is the go. Light external grime on the body/connector can be cleaned, but don’t scrub the sensing tip. If live data is implausible or codes persist after checking wiring and grounds, fit a new sensor.

Do I need to bleed the cooling system after changing the ECT sensor?
Yes. Removing the sensor lets air in. Refill with the correct coolant mix and bleed per the Serena FSM procedure so you don’t end up with hot spots, heater issues, or fan cycling problems. Keep an eye on the level over the next few drives.