P077A OBD-II: Output Speed Sensor Circuit - Loss of Direction Signal

P077A Severity

Urgent

Should you fix P077A yourself?

Identifying an OBD code is just the start of a complete diagnostic routine. Most trouble codes are caused by a sensor reporting a value that is out of range. Just replacing a sensor may not fix underlying issues. Be sure to understand the code, the part or system in your car that the code refers to, and the risks of delaying professional repair.

Proper diagnosis will save you time and money on unnecessary repairs.

Urgent codes indicate immediate action is necessary. These are urgent and significant malfunctions that can cause severe damage to the vehicle or harm the driver and passengers.

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What causes OBD-II fault code P077A?

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 P077A.

OBD II Fault Code

OBD II P077A

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

Transmission may not shift properly Symptoms

Increased fuel consumption
Transmission may not shift properly

Common Problems That Trigger the P077A Code

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

OBD Code Resources

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OBD II Fault Code

OBD II P077A

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

Transmission may not shift properly Symptoms

Increased fuel consumption
Transmission may not shift properly

Common Problems That Trigger the P077A Code

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

P077A OBD-II: Output Speed Sensor Circuit - Loss of Direction Signal

Should you fix P077A yourself?

What causes OBD-II fault code P077A?

Need a P077A diagnosis? Trust our experts.

OBD II Fault Code

Transmission may not shift properly Symptoms

Common Problems That Trigger the P077A Code

OBD Code Resources

Ask our experts about P077A.

Other OBD-II Codes

OBD II Fault Code

Transmission may not shift properly Symptoms

Common Problems That Trigger the P077A Code