P077A OBD II Trouble Code Output Speed Sensor Circuit - Loss Of Direction Signal

How to quickly diagnose, repair, and info on causes of a P077A trouble code which indicates a loss of direction signal from the output speed sensor circuit.

Symptoms of P077A OBD II Trouble Code

  • Intermittent speedometer/odometer operation
  • Abnormal transmission shift patterns
  • Transmission slippage or delayed engagement
  • Activation/deactivation of the traction control system (if applicable)
  • Other transmission and/or ABS codes may be stored

Common Causes of P077A OBD II Trouble Code

  • Defective output speed sensor
  • Metal debris on the output speed sensor
  • Open or shorted circuits or connectors (especially near the output speed sensor)
  • Damaged or worn reluctor ring
  • Mechanical transmission failure

Severity of P077A OBD II Trouble Code

The conditions which contribute to a code P077A being stored could result in (or be the result of) catastrophic transmission failure, it should be rectified with urgency.