AutoCodes – Chevrolet – P077D 2018 Chevrolet Silverado

P077D 2018 Chevrolet Silverado Code - Transmission Output Speed Sensor Circuit High Voltage

Quick Answer

The Output Speed Sensor (OSS) is a hall-effect type sensor. Common causes include Faulty Transmission Output Speed Sensor (OSS), Transmission Output Speed Sensor harness is open or shorted, Transmission Output Speed Sensor circuit poor electrical connection. 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 2018 Chevrolet Silverado indicates Transmission Output Speed Sensor Circuit High Voltage.
Common causes: Common causes include Faulty Transmission Output Speed Sensor (OSS), Transmission Output Speed Sensor harness is open or shorted, Transmission Output Speed Sensor circuit poor electrical connection.
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 Popularity 276

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Jul 29, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P077D 2018 Chevrolet Silverado Description

The Output Speed Sensor (OSS) is a hall-effect type sensor. The OSS mounts to the automatic transmission case assembly and connects to the control solenoid valve assembly through a 2-wire harness and connector. The sensor faces the park gear teeth. The sensor receives battery voltage on the OSS supply voltage circuit from the Transmission Control Module (TCM). As the output shaft rotates, the sensor produces a signal frequency based on the park gear teeth. This signal is transmitted through the OSS signal circuit to the TCM. The TCM uses the OSS signal to determine line pressure, transmission shift patterns, vehicle speed, and gear ratio.
The Diagnostic Trouble Code (DTC) will be set when the TCM detects the vehicle speed sensor signal circuit voltage is 4.75 V or greater for 0.8 s.

OBDII Code P077D 2018 Chevrolet Silverado - Transmission Output Speed Sensor Circuit High Voltage - AutoCodes.com — P077D 2018 Chevrolet Silverado Code - Transmission Output Speed Sensor Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P077D 2018 Chevrolet Silverado?

Faulty Transmission Output Speed Sensor (OSS)
Transmission Output Speed Sensor harness is open or shorted
Transmission Output Speed Sensor circuit poor electrical connection
Faulty Transmission Control Module (TCM)

How to Fix the DTC P077D 2018 Chevrolet Silverado?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P077D 2018 Chevrolet Silverado code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the P077D 2018 Chevrolet Silverado code?

Need more information on how to fix the P077D 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

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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.

Frequently Asked Questions about P077D 2018 Chevrolet Silverado Code

1. What are the common symptoms of an OBDII code P077D in a 2018 Chevrolet Silverado?

- Common symptoms include issues with shifting gears, harsh shifting, transmission slipping, and the transmission going into limp mode.

2. What can cause the OBDII code P077D to trigger in a 2018 Chevrolet Silverado?

- The code P077D is typically triggered by a malfunction in the transmission output speed sensor circuit, indicating high voltage readings.

3. How serious is the OBDII code P077D issue in a 2018 Chevrolet Silverado?

- The issue indicated by the code P077D can potentially lead to transmission performance issues and should be addressed promptly to prevent further damage.

4. Can driving with the OBDII code P077D in a 2018 Chevrolet Silverado cause further damage?

- Continuing to drive with the P077D code may exacerbate transmission problems, potentially leading to more severe issues and costly repairs.

5. How can the OBDII code P077D in a 2018 Chevrolet Silverado be diagnosed?

- Diagnosis typically involves using a scan tool to retrieve the code, followed by testing the transmission output speed sensor and related wiring for faults.

6. What are some DIY repair tips for the OBDII code P077D in a 2018 Chevrolet Silverado?

- DIY repair options include checking the wiring harness for damage, cleaning the sensor connector, and ensuring proper sensor alignment.

7. Is it recommended to reset the OBDII code P077D in a 2018 Chevrolet Silverado after repairs?

- Yes, it is advisable to clear the code after addressing the underlying issue to see if the problem has been successfully resolved.

8. Are there any recalls or service bulletins related to the OBDII code P077D in a 2018 Chevrolet Silverado?

- It's recommended to check with Chevrolet dealerships or online resources for any recalls or service bulletins addressing the P077D code in the 2018 Silverado.

9. How much does it typically cost to repair the OBDII code P077D in a 2018 Chevrolet Silverado?

- Repair costs can vary depending on the extent of the issue, but they may range from a few hundred to over a thousand dollars, including parts and labor.

10. What should I do if the OBDII code P077D persists in a 2018 Chevrolet Silverado after attempted repairs?

- If the P077D code continues to reappear after repairs, it may be necessary to seek professional help from a qualified mechanic or dealership for further diagnosis and repair.