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EngineModerate✅ DIY Friendly

P0117

Engine Coolant Temperature Circuit Low Input

ECT sensor voltage is lower than expected — ECM thinks engine is overheating.

SeverityModerate
CategoryEngine
Est. Repair Cost$30–$200
Code TypePowertrain
DIY RepairYes

⚡ Common Causes

  • ›Short to ground in ECT circuit
  • ›Faulty ECT sensor
  • ›Connector corrosion
  • ›Coolant contamination on sensor

⚠️ Symptoms

  • ›Cooling fan runs constantly
  • ›Engine runs rich
  • ›Check engine light
  • ›Temperature gauge reads high

✅ How to Fix — Step by Step

  • Step 1:Check sensor wiring for short to ground
  • Step 2:Clean sensor connector
  • Step 3:Replace ECT sensor
  • Step 4:Test coolant sensor resistance

🔧 Diagnostic Tools Required

Using the correct diagnostic tools helps identify the root cause of P0117 before replacing parts unnecessarily. Always confirm the fault using live data and manufacturer-recommended diagnostic procedures.

💡 Pro Tip: Cooling fan running constantly on cold startup is a telltale sign of P0117.

Repair Cost Estimate

Full Repair Estimate
$30–$200
DIY Possible?
YES
Severity
Moderate

Frequently Asked Questions

What does OBD2 code P0117 mean?+
P0117 stands for Engine Coolant Temperature Circuit Low Input. ECT sensor voltage is lower than expected — ECM thinks engine is overheating.
What causes code P0117?+
Short to ground in ECT circuit; Faulty ECT sensor; Connector corrosion; Coolant contamination on sensor
How do I fix code P0117?+
Check sensor wiring for short to ground; Clean sensor connector; Replace ECT sensor; Test coolant sensor resistance
How much does it cost to fix P0117?+
Estimated repair cost for P0117 is $30–$200.
Is P0117 DIY-friendly?+
Yes — P0117 is generally DIY-friendly with basic tools.

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