P077C Code - Transmission Output Speed Sensor Circuit Low Voltage
Quick Answer
The P077C code indicates an issue with the transmission output speed sensor circuit, specifically a low voltage condition. Common causes include Faulty transmission output speed sensor, Damaged wiring or connectors in the sensor circuit, PCM 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
- P077C indicates Transmission Output Speed Sensor Circuit Low Voltage.
- Common causes
- Common causes include Faulty transmission output speed sensor, Damaged wiring or connectors in the sensor circuit, PCM 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.
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Code P077C Description
The P077C code indicates an issue with the transmission output speed sensor circuit, specifically a low voltage condition. The transmission output speed sensor is a vital component that monitors the speed of the output shaft of the transmission. This information is crucial for the vehicle's powertrain control module (PCM) to adjust shift points and optimize performance. When the voltage from the sensor falls below the expected range, it can lead to various problems in the transmission's operation.
Common Causes of P077C
- Faulty transmission output speed sensor
- Damaged wiring or connectors in the sensor circuit
- PCM malfunction
- Low transmission fluid levels
- Mechanical issues within the transmission system
Symptoms of P077C
- Erratic shifting behavior
- Transmission slipping
- Lack of power or acceleration
- Decreased fuel efficiency
- Drivability issues
How to Fix P077C
- Diagnose the issue by using a scan tool to retrieve the code and test the transmission output speed sensor.
- Inspect the wiring and connectors for any damage or corrosion, repairing or replacing as needed.
- Check the transmission fluid level and condition, topping off or flushing the fluid if necessary.
- Test the PCM for any faults and reprogram or replace it if required.
- Clear the code from the PCM and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P077C
The typical repair costs for addressing a P077C code can range from $200 to $500, depending on the specific cause of the issue and the labor rates at the auto repair shop. Additional costs may be incurred if any parts need to be replaced. It is recommended to consult with a professional mechanic or dealership for a more accurate estimate based on the vehicle's make and model.
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Code P077C Information for Specific Makes
- P077C Buick — Transmission Output Speed Sensor Circuit Low Voltage
- P077C Cadillac — Transmission Output Speed Sensor Circuit Low Voltage
- P077C Chevrolet — Transmission Output Speed Sensor Circuit Low Voltage
- P077C GMC — Transmission Output Speed Sensor Circuit Low Voltage
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