P063F: Auto Configuration Engine Coolant Temperature Input Not Present

What it means

Auto Configuration Engine Coolant Temperature Input Not Present: the control module has detected this fault condition.

At a glance

• Usually lights the check-engine light
• Affects emissions; the car can fail an emissions test

How it works

During automatic configuration, the control module checks for an engine coolant temperature input. P063F sets when that temperature signal is absent, leaving the module without a reliable reading for cold-start fueling and cooling-fan decisions.

Common causes

Most likely first.

1. Coolant-temperature input signal absent during automatic configuration
2. Open or shorted coolant-temperature sensor wiring
3. Disconnected or faulty coolant-temperature sensor
4. Poor connector contact or sensor reference voltage

Symptoms

• Check engine light on
• Cooling fan runs constantly or not at all
• Cabin heater weak or excessively hot
• Possible long warm-up time or hard cold start

How to diagnose it

1. Read freeze-frame data and compare scan-tool coolant temperature with ambient temperature before starting a cold engine; an implausible or missing value points to the input fault.
2. Inspect the coolant-temperature sensor connector and wiring for looseness, corrosion, coolant intrusion, or damage.
3. Check the sensor reference, ground, and signal circuits against the manufacturer's specification.
4. Measure the sensor and its wiring for an open or short, using the manufacturer's procedure and temperature data to distinguish a failed sensor from a circuit fault.
5. After repair, confirm the scan-tool temperature rises smoothly as the engine warms and verify the cooling fan responds correctly.

Common fixes

• Reconnect the coolant-temperature sensor connector and clean or repair poor terminals.
• Repair an open, shorted, or damaged sensor wire.
• Replace the coolant-temperature sensor if its signal is absent or implausible with sound wiring.
• Restore a failed reference or ground supply to the sensor.
• Clear the code and confirm correct temperature and fan operation through a cold-to-warm cycle.

Can I keep driving?

Avoid driving if the temperature gauge indicates overheating or the cooling fan is not operating when needed; engine damage can follow quickly. If temperature indication and cooling appear normal, keep trips short and monitor the engine closely until the input is restored.