P0115 - Engine Coolant Temperature Circuit Malfunction
Problem detected in ECT sensor circuit.
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Common Next Steps
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Confirm external leaks, cap behavior, and pressure loss before parts.
Compare warm-up, scan temperature, and hose temperature behavior.
Check fan command, AC-load response, fuses, relays, and airflow.
Related Inspection
Code Overview
Problem detected in ECT sensor circuit.
Common Causes
- ECT sensor failed
- Wiring/connectors issue
- Low coolant/air pockets (can skew readings)
Diagnostic Steps
- Compare ECT to ambient when cold
- Inspect connector for coolant intrusion
- Bleed cooling system if needed
Likely Repairs & Cost Guides
Use symptoms, scan data, and quick checks to confirm the likely repair path before pricing parts. The estimator helps compare repair paths before replacing anything unnecessarily.
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Browse nearby code-family pages when the same fault pattern overlaps across systems, such as misfire, lean fuel trim, EVAP sealing, cooling, or charging faults.
Next Steps
Move from code lookup to diagnosis, then estimate the likely repair only after symptoms, causes, and checks point to the same path.