Product Function Description

The engine coolant temperature sensor (part number 22630-44B20) is a critical component of your Nissan or Infiniti‘s engine management system. Its primary function is to measure the temperature of the engine coolant and transmit this data to the engine control unit (ECU) via a variable resistance signal. The sensor uses a Negative Temperature Coefficient (NTC) thermistor, meaning its resistance decreases as coolant temperature rises. The ECU uses this signal to calculate critical parameters including fuel injection quantity and timing, ignition timing, variable valve timing, and automatic transmission shift strategy. On YD25 common-rail diesel engines, the ECU also uses this signal to control the glow plug controller . For compatible Nissan, Infiniti vehicles, a properly functioning coolant temperature sensor is essential for cold-start performance, fuel efficiency, and overall engine reliability.

 DIY Diagnosis Guide

How to Tell If Your Coolant Temperature Sensor Needs Replacement:

Look for these common signs:

1. Check engine light (P0115-P0118) – Codes related to coolant temperature circuit

2. Hard starting when cold – ECU receives incorrect temperature signal

3. Poor fuel economy – Incorrect fuel mixture due to faulty temperature data

4. Cooling fan runs constantly or not at all – Fan operation affected by sensor signal

5. Temperature gauge malfunction – Erratic or non-working gauge

💡 Quick inspection: Check the sensor connector for corrosion or damage. A scan tool can read live coolant temperature data and compare it to actual engine temperature. If the reading is significantly off, the sensor is likely faulty.

Product Attributes

Component Location & Core Function

Location: The engine coolant temperature sensor is located in a coolant passage on the engine, typically near the thermostat housing or in the water outlet tube close to the engine end of the upper radiator hose. On 4th generation Nissan Maxima, it is located in the water outlet tube, with the sensor nearest the hose being for the dashboard gauge and the ECTS (for the ECU) right next to it .

Connections: The sensor threads into the coolant passage with an M12 x 1.5 thread . It connects to the engine wiring harness via a 2-pin electrical connector (oval shape on some applications) . A sealing gasket or ring is used to prevent coolant leaks at the mounting point . The sensor body is typically blue or red in color .

Core Function: The coolant temperature sensor serves as the primary temperature feedback device for the engine management system. It continuously monitors coolant temperature and provides a resistance signal to the ECU that varies inversely with temperature (NTC type). The ECU uses this signal for multiple critical functions: adjusting fuel injection quantity and timing for cold and warm operation, controlling ignition timing, managing variable valve timing, determining automatic transmission shift points and torque converter lockup, and controlling glow plug operation on diesel engines . Without an accurate temperature signal, the ECU defaults to a preset value, causing drivability issues and increased emissions.

Why Choose This Coolant Temperature Sensor?

Restores Accurate Temperature Signal – A failing sensor sends incorrect temperature data to the ECU, causing cold-start issues, poor fuel economy, and transmission problems. This new sensor restores precise temperature feedback for optimal engine management.

Eliminates Cold-Start Problems – Worn sensors often cause hard starting and black smoke on diesel engines. This new sensor provides accurate cold-temperature signals for reliable starting and clean combustion.

Direct Replacement – Precision-engineered to match the original sensor specifications. Direct replacement – no modifications required. Part number 22630-44B20 is confirmed for compatible Nissan, Infiniti and Dacia applications .

Correct NTC Characteristics – Designed with the correct resistance curve (approximately 2080 ohms at 25°C, 294 ohms at 80°C) matching the original NTC thermistor for accurate temperature mapping .

Package Contents

1 x Engine Coolant Temperature Sensor (Part Number 22630-44B20) . Note: Electrical connector and mounting hardware are NOT included unless stated. Please confirm compatibility with your vehicle‘s model and engine before purchasing.

Step-by-Step Installation Guide

This installation guide is designed to help you replace your coolant temperature sensor with confidence. Before starting, ensure the engine is completely cool and the vehicle is parked on level ground. You will need the following tools: wrench (19mm or adjustable), multimeter, and coolant.

Step 1: Ensure the engine is completely cool. Place a container underneath the sensor to catch any coolant that may drain. Disconnect the negative battery cable.

Step 2: Locate the coolant temperature sensor. It is typically near the thermostat housing or in the water outlet tube near the upper radiator hose .

Step 3: Disconnect the electrical connector from the sensor by pressing the release tab and pulling it away.

Step 4: Remove the old sensor using a wrench. Turn counterclockwise to loosen. Clean the mounting threads and inspect the sealing surface.

Step 5: Install the new sensor with a new sealing gasket. Tighten securely but do not over-tighten (M12 x 1.5 thread requires moderate torque).

Step 6: Reconnect the electrical connector until it clicks into place. Top up the cooling system with the correct coolant mixture. Bleed air from the system.

Critical Step: Reconnect the negative battery cable. Start the engine and let it reach operating temperature. Observe the temperature gauge and check for coolant leaks around the sensor. Use a scan tool to verify the coolant temperature reading is accurate.

Pro Tip: When replacing the sensor, always use a new sealing gasket. Apply dielectric grease to the connector terminals to prevent corrosion. Check the coolant level after the engine cools down and top up if necessary.

Common Misconceptions About Coolant Temperature Sensors

Myth 1: The coolant temperature sensor and the temperature gauge sender are the same component.
Fact: On many Nissan and Infiniti vehicles, there are two separate sensors: one for the ECU (ECTS) and one for the dashboard gauge. They are located near each other but serve different functions. This sensor (22630-44B20) is the ECTS for the ECU .

Myth 2: A faulty coolant temperature sensor will always trigger a Check Engine Light immediately.
Fact: Intermittent sensor failures may not set a code until the failure becomes consistent. Many drivers experience cold-start issues or poor fuel economy without any warning light until the sensor fails completely.

Myth 3: Any coolant temperature sensor will work.
Fact: Coolant temperature sensors are engine-specific and must match the resistance curve (NTC characteristics), thread size, and connector type. This sensor is designed specifically for compatible Nissan, Infiniti and Dacia applications .

Common Customer Concerns & Our Solutions

We understand that purchasing a coolant temperature sensor can raise questions and concerns. Here is how we address the most common issues our customers face:

For Individual Vehicle Owners:

“How do I know if this sensor fits my vehicle?” – This sensor fits a wide range of Nissan, Infiniti vehicles. Please confirm your vehicle’s model and engine before ordering. The part number 22630-44B20 is the most reliable identifier and cross-references 22630-44B10, 22630-71L00, and 22630-0M200 .

“What if I install it and the car still has cold-start issues?” – Check that the connector is fully seated and the mounting threads are properly sealed. Verify no coolant leaks are present. Use a scan tool to check for any remaining fault codes. If codes persist, check the wiring harness for damage.

“Can I replace just the sensor without draining all the coolant?” – Yes, the sensor can be replaced quickly with minimal coolant loss if done when the engine is cold. Have a container ready to catch the small amount of coolant that may drain.

For Repair Shops and Professionals:

“Customer says the temperature gauge reads incorrectly after sensor replacement.” – Verify that the correct sensor was installed (ECTS for ECU, not the gauge sender). Check the connector and wiring. Use a scan tool to compare coolant temperature to intake air temperature when cold .

“How to avoid comebacks after sensor replacement?” – Use a new sealing gasket, torque the sensor properly, bleed the cooling system, and verify accurate temperature readings with a scan tool before returning the vehicle.

“Customer has a vehicle with a different engine – will this sensor work?” – This sensor is designed for specific Nissan, Infiniti applications. Verify the engine code and OE number before ordering.

After-Sales Service & Warranty

This product is covered by our quality assurance. If you have any questions or issues regarding fitment or quality, please contact us and we will respond within 24 hours.

Related Product Recommendations

When replacing the coolant temperature sensor, it is often recommended to inspect and consider replacing the following related components at the same time.