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1998 TOYOTA TACOMA
2.7L I4•RWD•AUTOMATIC•gas
5 active safety recalls on this vehicle — view recalls
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Repairs0Labor1040Torque1596Fluid17DTC3336Battery2Maintenance0Recalls5
P0691high severityPowertrain

Fan 1 Control Circuit Low

on 1998 Toyota Tacoma 2.7L I4 · RWD

What this code means

The PCM detected a low voltage condition in the cooling fan 1 control circuit. This means the fan may not run when commanded, risking engine overheating.

Symptoms

  • Engine overheating
  • Cooling fan not running
  • Check engine light on

Common causes

  • Short to ground in fan control wiring
  • Failed cooling fan relay
  • Faulty cooling fan motor
  • Damaged PCM output driver

Diagnostic steps

  1. Scan and confirm P0691 code
  2. Inspect fan control wiring for shorts
  3. Test fan relay and motor operation
  4. Check PCM fan control output signal
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