Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Code 14, Coolant Temp Sensor (Cts) CKT, Low Temp Indicated: Notes
CTS uses a thermistor to control signal voltage to ECM. ECM applies 5-volt signal to sensor. ECM monitors voltage across CTS and converts it into a temperature reading. When engine is cold, CTS resistance is high. As engine warms, sensor resistance lowers and voltage drops.
Code 14 will set when voltage input at ECM indicates coolant temperature at less than -54°F (-48°C) for at least 5 seconds.
- Simulates Code 15. If ECM stores Code 15, ECM and its wiring are okay and CTS is faulty. If Code 14 resets, CTS is okay and wiring to ECM or ECM is faulty.
- Determines whether an open exists in Red/Yellow or Gray/Yellow wires, a short to B+ exists in Red/Yellow wire or ECM is faulty.
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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.
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