P0118high severityPowertrain
ECT Sensor 1 Circuit High Input
on 1998 Audi A8 4.2L V8 · AWD
What this code means
The ECT sensor voltage is higher than expected, indicating very low temperature or open circuit.
Symptoms
- Check Engine Light
- Rich running at operating temp
- Poor fuel economy
- Fans not coming on
Common causes
- Open circuit
- Disconnected sensor
- Faulty sensor
- Corroded connector
Diagnostic steps
- Test sensor resistance
- Check for open circuits
- Inspect connector
Repair notes
Repair open circuit or replace sensor. CAUTION: Engine may overheat if fans do not activate.
🔌 Don't have a code reader?
Any of these will read and clear this code — pick by how deep you want to go.
Bluetooth code reader (~$25)
Veepeak OBDCheck BLE →
Pairs with your phone — reads and clears codes, live data.
Serious DIY (~$100)
BlueDriver Pro →
Enhanced codes (ABS, airbag, TPMS) plus repair reports.
Shop-grade tablet (~$300+)
Autel MaxiCOM MK808S →
Bidirectional tests, service resets, all systems.
As an Amazon Associate, OLP earns from qualifying purchases — how we link. This never changes the specs we publish.
Other Powertrain codes on this vehicle
00532
Supply Voltage B+ Signal too Low
16394
Camshaft/Crankshaft Position Correlation Bank 1
16395
Camshaft Position Actuator Circuit/Open Bank 1
16486
Mass or Volume Air Flow Circuit Low Input
16487
Mass or Volume Air Flow Circuit High Input
16500
Engine Coolant Temperature Circuit Malfunction
16501
Engine Coolant Temperature Circuit Low Input
16502
Engine Coolant Temperature Circuit High Input
16514
O2 Sensor Circuit Bank 1 Sensor 1
16515
O2 Sensor Circuit Low Voltage Bank 1 Sensor 1