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2003 INFINITI FX45
4.5L V8•AWD•AUTOMATIC•gas
9 active safety recalls on this vehicle — view recalls
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Repairs0Labor475Torque2094Fluid7DTC1778Battery1Maintenance0Recalls9
P1126moderate severityPowertrain

Thermostat Function

on 2003 Infiniti FX45 4.5L V8 · AWD

What this code means

Engine coolant temperature not reaching expected operating temperature.

Symptoms

  • CEL
  • Engine runs cold
  • Poor efficiency
  • Weak heater
  • Slow warm-up

Common causes

  • Thermostat stuck open
  • Faulty ECT sensor
  • Air in cooling system
  • Low coolant

Diagnostic steps

  1. Monitor coolant temp
  2. Test thermostat
  3. Check ECT sensor
  4. Inspect cooling system

Repair notes

Replace thermostat.

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