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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
P0642moderate severityPowertrain

Sensor Reference Voltage A Circuit Low

on 2003 Toyota Tacoma 2.7L I4 · RWD

What this code means

The PCM detected the sensor reference voltage on circuit A is below normal. Sensors relying on this reference may report faulty values.

Symptoms

  • Multiple sensor fault codes
  • Check engine light on
  • Poor engine performance

Common causes

  • Short to ground on reference circuit
  • Faulty sensor pulling reference down
  • Damaged wiring
  • Faulty PCM

Diagnostic steps

  1. Measure reference voltage at sensors
  2. Inspect wiring for short to ground
  3. Disconnect sensors one at a time to isolate
  4. Repair circuit or replace PCM
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