P077C 2018 GMC Sierra Code - Transmission Output Speed Sensor Circuit Low Voltage
Quick Answer
The P077C diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates a problem with the transmission output speed sensor circuit registering low voltage. Common causes include Faulty transmission output speed sensor, Damaged wiring or connectors in the sensor circuit, Corrosion or debris affecting sensor operation. 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 2018 GMC Sierra 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, Corrosion or debris affecting sensor operation.
- 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 2018 GMC Sierra Description
The P077C diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates a problem with the transmission output speed sensor circuit registering low voltage. The transmission output speed sensor is a crucial component that monitors the speed of the output shaft of the transmission. This information is essential for the vehicle's onboard computer to determine the appropriate shift points for optimal performance and fuel efficiency. When the sensor detects low voltage, it means that there is a malfunction in the circuit, which can lead to various issues with the vehicle's transmission system.
Common Causes of P077C 2018 GMC Sierra
- Faulty transmission output speed sensor
- Damaged wiring or connectors in the sensor circuit
- Corrosion or debris affecting sensor operation
- Issues with the transmission control module
- Electrical problems within the transmission system
Symptoms of P077C 2018 GMC Sierra
- Harsh or delayed shifting
- Poor acceleration
- Reduced fuel efficiency
- Limp mode activation
- Illumination of the Check Engine Light
How to Fix P077C 2018 GMC Sierra
- Begin by diagnosing the specific cause of the low voltage in the transmission output speed sensor circuit using a diagnostic scanner.
- Inspect the sensor, wiring, and connectors for any visible damage, corrosion, or loose connections.
- Test the sensor's resistance and voltage output to determine if it is functioning correctly.
- Replace the transmission output speed sensor if it is found to be faulty, ensuring proper installation and connection.
- Clear the DTC from the vehicle's computer and test drive the vehicle to ensure the issue has been resolved.
Cost to Fix P077C 2018 GMC Sierra
The cost of repairing a transmission output speed sensor circuit with low voltage can vary depending on the specific cause of the issue and the labor rates in your area. Typically, the cost of replacing the sensor itself ranges from $100 to $300, with additional costs for labor. Overall, the total repair cost can range from $200 to $500 or more. It is advisable to consult with a trusted mechanic or dealership to get an accurate estimate based on your vehicle's make and model. Keep in mind that diagnostic time and labor rates can vary, so it's essential to inquire about these factors when obtaining a repair quote.
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