P1116 CHEVROLET – Engine Coolant Temperature Sensor Signal Unstable or Intermittent

Posted by

📌 Meaning of Code P1116

The code P1116 is related to the Engine Coolant Temperature (ECT) sensor.
This sensor uses a thermistor, a semiconductor device whose resistance varies with temperature.

The ECT sensor is usually mounted on the left cylinder head, near the front of the engine. It has:

  • A signal circuit
  • A ground circuit

The PCM (Powertrain Control Module) sends a voltage (~5 V) to the sensor via the signal circuit. Depending on the temperature:

  • When cold: high resistance → high signal voltage
  • When hot: low resistance → lowered signal voltage

When the returned values do not match the expected normal ranges, the PCM triggers the P1116 code.


🚨 Possible Symptoms

  • Check Engine light on
  • Possible symptoms related to poor engine thermal management (e.g., overheating or hard cold starts)

❗ Possible Causes

  • Low engine coolant level
  • Faulty ECT sensor
  • Open or shorted ECT sensor harness
  • Poor electrical connection in the ECT sensor circuit
  • Faulty engine thermostat

🛠️ How to Fix Code P1116 Chevrolet

  1. Check all the possible causes listed above first.
  2. Visually inspect the wiring harness and associated connectors.
  3. Look for:
    • Damaged wires
    • Broken, bent, pushed, or corroded connector pins
  4. Also check:
    • The coolant level
    • The proper operation of the thermostat
    • The ECT sensor using a multimeter or via a diagnostic tool

Leave a Reply

Your email address will not be published. Required fields are marked *