Engine-CodesGeneric – P077D

P077D Code - Transmission Output Speed Sensor Circuit High Voltage

Quick Answer

The P077D diagnostic trouble code (DTC) refers to a Transmission Output Speed Sensor Circuit High Voltage. Common causes include Faulty transmission output speed sensor, Wiring issues in the transmission output speed sensor circuit, ECM malfunction. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
P077D indicates Transmission Output Speed Sensor Circuit High Voltage.
Common causes
Common causes include Faulty transmission output speed sensor, Wiring issues in the transmission output speed sensor circuit, ECM malfunction.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P077D Description

The P077D diagnostic trouble code (DTC) refers to a Transmission Output Speed Sensor Circuit High Voltage. This code indicates that there is an issue with the transmission output speed sensor circuit where the voltage is higher than the specified range. The transmission output speed sensor is a crucial component that measures the speed of the output shaft of the transmission. This information is used by the vehicle's engine control module (ECM) to determine shift points and optimize transmission performance.

OBDII Code P077D - Transmission Output Speed Sensor Circuit High Voltage
P077D Code - Transmission Output Speed Sensor Circuit High Voltage

Common Causes of P077D

  1. Faulty transmission output speed sensor
  2. Wiring issues in the transmission output speed sensor circuit
  3. ECM malfunction
  4. Corrosion or damage to sensor connectors
  5. Transmission fluid contamination

Symptoms of P077D

  1. Erratic shifting patterns
  2. Harsh shifting
  3. Delayed shifting
  4. Transmission going into limp mode
  5. Poor fuel efficiency

How to Fix P077D

  1. Begin by conducting a thorough diagnosis of the transmission output speed sensor circuit using a scan tool to pinpoint the exact cause of the high voltage issue.
  2. Inspect the wiring harness and connectors for any signs of damage, corrosion, or loose connections. Repair or replace any faulty wiring.
  3. Test the transmission output speed sensor for proper functionality and replace it if necessary.
  4. Clear the DTC from the ECM and reset the system to ensure that the issue has been resolved.
  5. Test drive the vehicle to verify that the transmission is shifting correctly and that the high voltage issue has been addressed.

Cost to Fix P077D

The typical repair costs for addressing a Transmission Output Speed Sensor Circuit High Voltage issue can range from $150 to $400, depending on the extent of the problem and the cost of parts needed for the repair. Labor costs can vary based on location, with rates typically ranging from $80 to $150 per hour. It is recommended to check with local auto repair shops for a more accurate estimate based on the specific make and model of the vehicle.

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Code P077D Information for Specific Makes

  • P077D Buick — Transmission Output Speed Sensor Circuit High Voltage
  • P077D Cadillac — Transmission Output Speed Sensor Circuit High Voltage
  • P077D Chevrolet — Transmission Output Speed Sensor Circuit High Voltage
  • P077D GMC — Transmission Output Speed Sensor Circuit High Voltage
About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

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