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2004 FORD THUNDERBIRD
3.8L V6•FWD•AUTOMATIC•gas
1 active safety recall on this vehicle — view recalls
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Repairs0Labor484Torque484Fluid7DTC1721Battery1Maintenance0Recalls1
P0674low severityPowertrain

Cylinder 4 Glow Plug Circuit

on 2004 Ford Thunderbird 3.8L V6 · FWD

What this code means

The PCM detected a fault in the glow plug control circuit for cylinder 4. This can cause hard starting and rough running in cold conditions on diesel engines.

Symptoms

  • Hard cold starting
  • Rough idle when cold
  • Glow plug warning light

Common causes

  • Faulty glow plug cylinder 4
  • Corroded glow plug wiring
  • Bad glow plug control module
  • Blown glow plug fuse

Diagnostic steps

  1. Scan for related glow plug codes
  2. Measure resistance of cylinder 4 glow plug
  3. Check wiring and connectors to glow plug
  4. Test glow plug control module output
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