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2003 TOYOTA TACOMA
2.7L I4•RWD•AUTOMATIC•gas•3RZ-FE
5 active safety recalls on this vehicle — view recalls
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Repairs0Labor1047Torque1633Fluid17DTC3480Battery2Maintenance0Recalls5
P0684moderate severityPowertrain

Glow Plug Control Module to PCM Communication Circuit Range/Performance

on 2003 Toyota Tacoma 2.7L I4 · RWD

What this code means

The PCM detects an out-of-range or implausible signal in communication with the glow plug control module. Glow plug timing and operation may be incorrect.

Symptoms

  • Difficult cold starting
  • Glow plug light flashing
  • White exhaust smoke when cold

Common causes

  • Damaged communication wiring
  • Poor connector contact
  • Faulty glow plug control module
  • PCM software fault

Diagnostic steps

  1. Retrieve related fault codes
  2. Inspect and test communication wiring
  3. Check for correct reference voltage
  4. Test or replace glow plug module
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Other Powertrain codes on this vehicle

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