16500moderate severityPowertrain
Engine Coolant Temperature Circuit Malfunction
on 1999 Audi A6 2.8L V6 · AWD
What this code means
The engine coolant temperature sensor circuit is malfunctioning (OBD P0116). The signal is erratic or out of expected range.
Symptoms
- Poor cold start
- Check engine light on
- Erratic temperature gauge
Common causes
- Faulty coolant temperature sensor
- Wiring or connector fault
- Low coolant level
- Thermostat stuck
Diagnostic steps
- Read live coolant temp data
- Compare with actual engine temperature
- Inspect sensor wiring and connector
- Test sensor resistance across temperatures
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