GM GENUINE PARTS Engine Coolant Temperature Sensor 213-4688 (55591002) — OE Fit, Accurate Temp Signal

This GM-recommended coolant temperature sensor is built to the same specifications as the factory-installed unit, ensuring proper fit, signal accuracy, and durability for compatible GM vehicles. It measures coolant temperature and sends that data to the engine control module so fuel delivery and ignition timing can be adjusted. Choosing an OE sensor helps maintain factory calibration and avoid drivability issues caused by incorrect temperature readings.

How does this sensor affect engine performance?

The sensor provides the engine control module with a real-time temperature signal, which the ECU uses to optimize fuel injection and ignition timing. A correct reading supports efficient combustion, smoother idle, and predictable throttle response. Replacing a faulty sensor often resolves rough idle, hard starting, and excess fuel consumption.

• Transmits coolant temperature data to the ECU for air/fuel adjustments
• Helps maintain proper cold-start enrichment and warm-up strategy
• Prevents erratic idle and poor fuel economy caused by false readings

Will this part fit my GM vehicle and match OEM standards?

Yes — the 213-4688 (55591002) is manufactured to GM original equipment specifications to match the form, fit, and function of the factory unit. It’s supplied as a GM Genuine Parts item, which reduces the risk of fitment problems and simplifies installation. Always verify part number compatibility with your vehicle’s year, make, and model before purchase.

• GM OE specification for physical dimensions and electrical characteristics
• Designed to match factory connector and thread size for direct replacement
• Recommended by GM as the correct replacement for certain applications

How do I spot a failing coolant temperature sensor?

Symptoms include unstable idle, increased fuel consumption, difficulty starting when cold, and engine warning lights related to engine management. Electrical testing with a multimeter or scan tool can confirm signal anomalies. If the sensor’s resistance or voltage output is outside factory tolerances, replacement is advisable.

• Look for check engine light codes related to coolant temp or sensor circuit
• Noticeable changes in idle quality and cold-start behavior
• Use diagnostic tools to verify sensor output before replacing other components

What should I know about installation and maintenance?

Installation is typically straightforward: drain a small amount of coolant, unplug the electrical connector, remove the old sensor, and fit the new unit with the appropriate sealant or gasket. Torque to manufacturer specifications and refill the cooling system, then purge air pockets as required. Routine inspection during coolant service helps avoid unexpected failures.

• Drain or relieve coolant pressure to prevent fluid loss during removal
• Replace with GM 213-4688 (55591002) for guaranteed compatibility
• Tighten to recommended torque and bleed the cooling system afterward

Who is this for: The GM Genuine Parts 213-4688 (55591002) sensor is intended for owners and technicians who want an OE-grade replacement for GM vehicles that use this part number. It’s ideal for repairs where maintaining factory calibration and long-term reliability are priorities — particularly during routine cooling system service or when diagnosing engine management issues linked to temperature sensing. If you value correct fitment, consistent sensor output, and the confidence of a GM-recommended component, this sensor meets those needs.