P077C 2014 GMC Sierra Code - Transmission Output Speed Sensor Circuit Low Voltage
Quick Answer
The P077C diagnostic trouble code (DTC) for a 2014 GMC Sierra indicates an issue with the transmission output speed sensor circuit registering low voltage. Common causes include Faulty transmission output speed sensor, Damaged or corroded wiring/connectors in the sensor circuit, Issues with the TCM. 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 2014 GMC Sierra indicates Transmission Output Speed Sensor Circuit Low Voltage.
- Common causes
- Common causes include Faulty transmission output speed sensor, Damaged or corroded wiring/connectors in the sensor circuit, Issues with the TCM.
- 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 2014 GMC Sierra Description
The P077C diagnostic trouble code (DTC) for a 2014 GMC Sierra indicates an issue with the transmission output speed sensor circuit registering low voltage. 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 transmission control module (TCM) to determine the appropriate shift points and ensure smooth operation of the transmission.
Common Causes of P077C 2014 GMC Sierra
- Faulty transmission output speed sensor
- Damaged or corroded wiring/connectors in the sensor circuit
- Issues with the TCM
- Electrical problems in the transmission control system
- Fluid contamination affecting sensor performance
Symptoms of P077C 2014 GMC Sierra
- Erratic shifting patterns
- Harsh shifting
- Delayed engagement when shifting gears
- Transmission going into limp mode
- Illumination of the Check Engine Light
How to Fix P077C 2014 GMC Sierra
- Begin by conducting a thorough diagnostic scan to confirm the P077C code and pinpoint the exact cause of the issue.
- Inspect the transmission output speed sensor and its wiring/connectors for any visible damage or corrosion. Replace the sensor if necessary.
- Test the sensor circuit for continuity and proper voltage levels to ensure it is functioning correctly.
- If the sensor and wiring are in good condition, check the TCM for any faults or malfunctions. Repair or replace the TCM as needed.
- Clear the DTC and test drive the vehicle to verify that the issue has been resolved and that the transmission is operating smoothly.
Cost to Fix P077C 2014 GMC Sierra
The typical repair costs for addressing a transmission output speed sensor circuit low voltage issue can vary depending on the specific cause of the problem and the labor rates in your area. In general, replacing the sensor itself can cost between $100 and $300, while addressing wiring or TCM issues may increase the total repair cost. Overall, you can expect to pay anywhere from $200 to $600 for parts and labor. Keep in mind that diagnostic time and labor rates at auto repair shops can fluctuate, so it's advisable to obtain quotes from multiple sources to ensure a competitive price.
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