Engine Coolant Temperature Sensor Not Detected
The Powertrain Control Module (PCM) has detected that the engine coolant temperature (ECT) sensor input is missing or not configured. This sensor is critical for engine management, including fuel mixture and cooling fan control. The code indicates a communication or circuit fault, often due to a faulty sensor, wiring issue, or PCM configuration error.
01. Most Common Causes
- Faulty engine coolant temperature sensor
- Open or shorted wiring in the ECT sensor circuit
- Corroded or loose connector at the ECT sensor
- PCM software or configuration issue
02. Symptoms You Will Notice
- Check Engine Light illuminated
- Engine may run rich or lean, causing poor fuel economy
- Cooling fans may run continuously or not at all
- Engine may overheat or run cold
03. Step-by-Step Diagnosis
Step 1: Use a scan tool to verify the code and check for related codes.
Step 2: Inspect the ECT sensor connector for corrosion, damage, or loose pins.
Step 3: Measure resistance across the ECT sensor terminals; compare to manufacturer specs.
Step 4: Check for 5V reference and ground at the sensor connector with the ignition on.
Step 5: If wiring and sensor are good, perform a PCM configuration or reprogramming.
04. Commonly Affected Makes
05. Frequently Asked Questions
Is it safe to drive with this code?▼
It is not recommended as the engine may run poorly, overheat, or cause further damage. Have it diagnosed promptly.
How much does it cost to fix?▼
Typically $50-$150 for sensor replacement, plus diagnostic fees. PCM reprogramming may add $100-$200.