P0115moderate severityPowertrain
Engine Coolant Temperature (ECT) Sensor 1 Circuit
on 2022 BMW i4 eDrive35 Single Motor RWD · RWD
What this code means
General malfunction in the engine coolant temperature sensor circuit.
Symptoms
- Check Engine Light
- Poor fuel economy
- Hard starting
- Incorrect temp gauge reading
- Fans not operating correctly
Common causes
- Faulty ECT sensor
- Wiring damage
- Corroded connector
- Low coolant level
Diagnostic steps
- Test ECT resistance at known temperature
- Inspect wiring
- Check coolant level
- Compare ECT to IAT at cold start
Repair notes
Replace ECT sensor or repair wiring. Verify coolant level.
🔌 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
29CC
Misfire Cylinder 1
29CD
Misfire Cylinder 2
29CE
Misfire Cylinder 3
29CF
Misfire Cylinder 4
29D0
Misfire Cylinder 5
29D1
Misfire Cylinder 6
29D2
Misfire Cylinder 7
29E0
Lambda Additive/Idle Adaptation Limit, Bank 1
29E1
Lambda Additive/Idle Adaptation Limit, Bank 2
29E2
Lambda Multiplicative Part-Load Adaptation Limit, Bank 1