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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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Repairs0Labor1050Torque1637Fluid17DTC3334Battery2Maintenance0Recalls5
P0839moderate severityPowertrain

Four Wheel Drive (4WD) Switch Circuit High

on 1998 Toyota Tacoma 2.7L I4 · RWD

What this code means

The PCM detects an abnormally high voltage on the 4WD selector switch circuit. This can prevent proper engagement of four-wheel drive modes.

Symptoms

  • 4WD does not engage
  • Warning light on dash
  • Erratic 4WD mode selection

Common causes

  • Faulty 4WD selector switch
  • Short to voltage in wiring
  • Corroded switch connector
  • Failed transfer case control module

Diagnostic steps

  1. Scan for stored codes and freeze frame
  2. Inspect 4WD switch connector and wiring
  3. Measure switch signal voltage with meter
  4. Replace switch if out of spec
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