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2002 MAZDA 626
2.0L I4•FWD•AUTOMATIC•gas
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Repairs0Labor499Torque3155Fluid7DTC910Battery1Maintenance0Recalls0
B0404low severityBody

Temperature Gauge Circuit Malfunction

on 2002 Mazda 626 2.0L I4 · FWD

What this code means

The engine temperature gauge in the instrument cluster is not functioning or reads incorrectly.

Symptoms

  • Temperature gauge stuck at cold
  • Gauge stuck at hot
  • Temperature gauge erratic
  • No temperature warning capability

Common causes

  • Faulty coolant temperature sender for gauge
  • Cluster gauge failure
  • Wiring issue
  • Sender connector corroded

Diagnostic steps

  1. Check coolant temp sender resistance
  2. Test gauge with simulated resistance
  3. Inspect sender connector
  4. Compare scan tool temp to gauge reading

Repair notes

Replace coolant temperature sender for gauge (separate from ECT sensor) or repair cluster.

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