Parts for your 2000 Toyota Crown-Temperature sensors

2000 Toyota Crown temperature sensors — what they do and how to look after them

Temperature sensors are absolutely fitted to the 2000 Toyota Crown (S170 series). Toyota’s factory repair literature for the S170 Crown (1999–2003) — including the Engine Control System sections for 1G‑FE and 1JZ‑FSE engines, the Automatic Transmission manual, the Air Conditioning manual, and the Electrical Wiring Diagram (EWD) — lists multiple temperature inputs. These include the Engine Coolant Temperature (ECT/THW) sensor, intake air temperature, ambient air temperature for the climate control, evaporator temperature, and automatic‑transmission fluid (ATF) temperature sensors. They’re core to fuelling, ignition timing, idle speed, fan control, the dash gauge, and cabin comfort.

On the Crown, these sensors are thermistors that change resistance with heat. The ECT sensor tells the engine ECU how warm the motor is so it can adjust cold‑start enrichment and timing, it also helps trigger the radiator fans. Many Crowns of this era also use a separate sender for the dash gauge. The climate system relies on ambient and evaporator temperature sensors to keep the cabin comfy without fogging, while the transmission uses an internal temp sensor to protect the gearbox and tune shift quality.

There’s no set replacement interval for temperature sensors, but a bit of care during routine servicing pays off. At each coolant change (Toyota red LLC typically every 2 years or around 40–50,000 km, unless the service schedule for the specific variant says otherwise), inspect the ECT sensor connector for corrosion or broken tabs, check for coolant weeps around the sensor boss, and make sure the radiator fans cycle normally. If the Crown shows hard cold starts, rich running, poor fuel economy, a high idle, or fans stuck on, scan for fault codes such as P0115–P0119 and compare live data to an infrared thermometer at the thermostat housing.

• Typical ECT resistance checks: roughly 2–3 kΩ at 20°C and 200–300 Ω at 80–90°C (verify against the exact engine spec in the Toyota manual).
• Location: commonly on the water outlet/thermostat housing near the cylinder head, the dash sender may sit nearby.
• Replacement tips: work on a cool engine, relieve pressure, drain a little coolant, unplug the connector, and swap the sensor using a deep socket. Fit a new sealing washer if specified and tighten to the workshop spec (around 18–22 N·m on many Toyotas, confirm for your engine). Refill, bleed the cooling system, and check for leaks.

Technical sources referenced: Toyota Crown S170 Repair Manual (Engine Control System: 1G‑FE, 1JZ‑FSE), Toyota Electrical Wiring Diagram (S170 Series), Toyota Automatic Transmission and Air Conditioning manuals for S170.

Popular questions about 2000 Toyota Crown temperature sensors

Where’s the coolant temperature sensor on a 2000 Crown?
On most S170 Crowns it’s threaded into the water outlet/thermostat housing on the engine, close to the cylinder head. Some variants also have a separate sender for the dash gauge nearby, so it’s easy to mix them up. If unsure, follow the THW circuit in the EWD for your exact engine code.

Do temperature sensors need routine replacement?
No routine interval — they’re replaced on condition. Include connector checks and a quick scan of ECT data during regular servicing. Replace the sensor if readings are out of spec, there are related fault codes, or there’s evidence of coolant intrusion.

Can a bad temperature sensor really affect fuel economy?
Yes. If the ECT reads cold all the time, the ECU enriches the mixture, burning more fuel and washing oil from the bores. It can also mess with idle quality and fan operation. Fixing a lazy sensor often restores normal economy and drivability.