P077B - OBD II Trouble Code

Our automotive experts have put together the following information about the P077B diagnostic trouble code. We've provided the common symptoms that occur when this code is set along with the frequent repairs that address the issues related to the P077B code.

OBD II Fault Code

• OBD II P077B

OBD-II Code Transmission may not shift properly is defined as a Output Speed Sensor Circuit - Direction Error

The Output Speed Sensor tells the Transmission Control Module (TCM) how fast the output shaft of the transmission is spinning so it can verify the correct gear is engaged. Some manufacturers add a second Output Shaft Speed Sensor to enable the TCM to determine what direction the shaft is rotating. When the TCM receives an implausible signal from these sensors, the engine control module (PCM) or Hybrid Control Module will set code P077B.

Transmission may not shift properly Symptoms

• Increased fuel consumption
• Transmission may not shift properly

Common Problems That Trigger the P077B Code

• High voltage control module failure
• Output shaft speed sensor failure
• Transmission Control Module (TCM) failure
• Wiring issue