P0721 2016 GMC Sierra Code - Transmission Output Speed Sensor Performance
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
- P0721 2016 GMC Sierra indicates Transmission Output Speed Sensor Performance.
- 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.
Code P0721 2016 GMC Sierra Description
The Diagnostic Trouble Code (DTC) will be set when the TCM detects a noisy output speed signal.
What are the Possible Causes of the DTC P0721 2016 GMC Sierra?
- 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 P0721 2016 GMC Sierra?
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 P0721 2016 GMC Sierra 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.
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Frequently Asked Questions about P0721 2016 GMC Sierra Code
1. What does the OBDII code P0721 mean for a 2016 GMC Sierra?
P0721 indicates an issue with the transmission output speed sensor performance, where the sensor is not providing accurate readings to the vehicle's computer.
2. What are common symptoms of code P0721 in a 2016 GMC Sierra?
Symptoms may include erratic or harsh shifting, the transmission staying in one gear, inaccurate speedometer readings, and the check engine light being illuminated.
3. What causes the P0721 code to appear in a 2016 GMC Sierra?
Common causes include a faulty output speed sensor, damaged wiring or connectors, transmission fluid issues, or problems with the transmission control module (TCM).
4. Can I still drive my 2016 GMC Sierra with the P0721 code active?
Driving with this code is not recommended, as it can lead to transmission damage or unsafe driving conditions due to erratic shifting.
5. How do I diagnose the P0721 code on my 2016 GMC Sierra?
Diagnosis involves scanning for additional codes, inspecting the output speed sensor and its wiring, checking transmission fluid levels, and testing the sensor with a multimeter.
6. How do I fix the P0721 code on a 2016 GMC Sierra?
Fixes may include replacing the output speed sensor, repairing damaged wiring, topping off or replacing transmission fluid, or reprogramming the transmission control module.
7. How much does it cost to repair the P0721 code on a 2016 GMC Sierra?
Repair costs vary but typically range from $100 to $300 for sensor replacement, with higher costs if wiring issues or TCM repairs are needed.
8. Where is the transmission output speed sensor located on a 2016 GMC Sierra?
The output speed sensor is usually located on the transmission housing near the output shaft.
9. Can low transmission fluid cause the P0721 code in a 2016 GMC Sierra?
Yes, low or dirty transmission fluid can cause erratic sensor readings and trigger the P0721 code.
10. Will clearing the P0721 code fix the problem on my 2016 GMC Sierra?
Clearing the code will temporarily turn off the check engine light, but the issue will likely return unless the underlying problem is resolved.
Discuss the causes and fixes for P0721 2016 GMC Sierra OBDII Code
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