Coolant Temperature Sensor/Switch (For Computer): Description and Operation

1991 Volkswagen Jetta L4-1984cc 2.0L DOHCSECTION Description and Operation

Coolant Temperature Sensor:





The coolant temperature sensor, which is located at the transmission side of the cylinder head near the water outlet, senses the temperature of the coolant.

Coolant Temperature Sensor:





The sensor is a negative temperature coefficient (NTC) resistor, which means that its resistance decreases as coolant temperature increases.





The signal from the temperature sensor enables the Motronic control unit to calculate the necessary correction values for fuel enrichment, ignition timing, idle stabilization, and evaporative emission operation during starting and engine warm-up operations.
RENDER: 1.0x

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • You smell fuel, burning insulation, or see smoke.
  • Brakes feel soft, pull hard to one side, or make grinding noises.
  • The engine overheats, stalls repeatedly, or misfires under load.
  • You are missing required tools, torque specs, or safe lifting equipment.
  • You are not confident in the next step or safety outcome.