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P179B 2016 GMC Sierra Code - Transmission Range State Command Signal Message Counter Incorrect

Quick Answer

The P179B code indicates a discrepancy in the transmission range state command signal message counter within the 2016 GMC Sierra. Common causes include Faulty transmission range sensor or switch, Damaged or corroded wiring and connectors between the TCM and ECM, Software issues or glitches in the TCM or ECM. 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
P179B 2016 GMC Sierra indicates Transmission Range State Command Signal Message Counter Incorrect.
Common causes
Common causes include Faulty transmission range sensor or switch, Damaged or corroded wiring and connectors between the TCM and ECM, Software issues or glitches in the TCM or ECM.
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.
What is this?
Table of contents Created and updated by William Orellana on Oct 18, 2024
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Code P179B 2016 GMC Sierra Description

The P179B code indicates a discrepancy in the transmission range state command signal message counter within the 2016 GMC Sierra. This code is part of the vehicle's onboard diagnostics and is related to the communication between the transmission control module (TCM) and the engine control module (ECM). The transmission range state command signal is crucial for ensuring that the vehicle operates in the correct gear and that the transmission behaves as expected. When the message counter is incorrect, it suggests that there may be a communication issue, which can lead to improper gear selection, erratic shifting, or even failure to shift altogether.

OBDII Code P179B 2016 GMC Sierra - Transmission Range State Command Signal Message Counter Incorrect
P179B 2016 GMC Sierra Code - Transmission Range State Command Signal Message Counter Incorrect

Common Causes of P179B 2016 GMC Sierra

  1. Faulty transmission range sensor or switch.
  2. Damaged or corroded wiring and connectors between the TCM and ECM.
  3. Software issues or glitches in the TCM or ECM.
  4. Low transmission fluid levels or contaminated fluid affecting sensor performance.
  5. Mechanical issues within the transmission itself, such as worn components.

Symptoms of P179B 2016 GMC Sierra

  1. Erratic or harsh shifting between gears.
  2. Vehicle may enter limp mode, restricting speed and power.
  3. Delayed engagement when shifting from park to drive or reverse.
  4. Warning lights illuminated on the dashboard, including the check engine light.
  5. Unusual noises from the transmission, such as grinding or whining.

How to Fix P179B 2016 GMC Sierra

  1. Diagnostic Scan: Begin with a thorough diagnostic scan to confirm the P179B code and check for any related codes that may provide additional context.
  2. Visual Inspection: Inspect wiring and connectors for damage, corrosion, or loose connections. Repair or replace any faulty components as necessary.
  3. Sensor Testing: Test the transmission range sensor and switch to ensure they are functioning correctly. Replace if found defective.
  4. Software Update: Check for any available software updates for the TCM and ECM. If updates are available, perform the updates to ensure proper communication.
  5. Fluid Check: Inspect the transmission fluid level and condition. If low or contaminated, perform a fluid change and refill to the appropriate level.

Cost to Fix P179B 2016 GMC Sierra

The cost to repair the P179B code can vary widely based on the specific cause of the issue. On average, repairs may range from $200 to $1,500. Simple fixes like replacing a faulty sensor may cost around $200 to $400, while more extensive repairs involving wiring harness replacements or transmission service could escalate to $1,000 or more. Labor rates typically range from $80 to $150 per hour, depending on the shop's location and reputation. Metropolitan areas and dealerships often charge higher rates, while independent shops may offer more competitive pricing. It is advisable to obtain quotes from local repair shops for a more accurate estimate tailored to your specific situation.

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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 P179B 2016 GMC Sierra Code

1. What are the common symptoms of OBDII code P179B in a 2016 GMC Sierra?

- Common symptoms include transmission shifting issues, hesitation or jerking during gear changes, and the transmission being stuck in a single gear.

2. What causes the OBDII code P179B to appear in a 2016 GMC Sierra?

- The code typically indicates that the Transmission Range State Command Signal Message Counter is incorrect, which may be caused by a faulty transmission range sensor, wiring issues, or a malfunctioning transmission control module.

3. How serious is the OBDII code P179B in a 2016 GMC Sierra?

- This code indicates a problem with the transmission range state command signal, which can potentially lead to drivability issues and affect the overall performance of the vehicle. It is recommended to address this issue promptly.

4. Can I continue driving my 2016 GMC Sierra with the OBDII code P179B?

- It is not recommended to continue driving the vehicle with this code present, as it can lead to further transmission problems and potentially cause damage if left unresolved.

5. How can I diagnose the OBDII code P179B in my 2016 GMC Sierra?

- To diagnose this code, a professional diagnostic scan tool is typically used to retrieve the specific fault codes from the vehicle's computer system. Additionally, a thorough inspection of the transmission range sensor and related components may be necessary.

6. What are some repair tips for addressing the OBDII code P179B in a 2016 GMC Sierra?

- Repair tips may include checking and repairing any damaged wiring, replacing the transmission range sensor if faulty, or resetting the transmission control module to see if the code reoccurs.

7. How much does it generally cost to repair the OBDII code P179B in a 2016 GMC Sierra?

- The cost of repairing this code can vary depending on the underlying cause and the specific components that need to be replaced. It is advisable to consult with a professional mechanic for an accurate estimate.

8. Can a DIY enthusiast fix the OBDII code P179B in a 2016 GMC Sierra?

- While some basic troubleshooting and repairs can be done by a DIY enthusiast, diagnosing and fixing complex transmission issues like this code may require specialized tools and expertise. It is recommended to seek professional help if unsure.

9. Will resetting the OBDII code P179B in a 2016 GMC Sierra make it go away permanently?

- Resetting the code may temporarily clear the warning light, but if the underlying issue causing the code is not addressed, it is likely to reappear. It is crucial to diagnose and fix the root cause to prevent future occurrences.

10. How often does the OBDII code P179B occur in a 2016 GMC Sierra?

- The frequency of this code occurrence can vary depending on driving habits, maintenance history, and the overall condition of the vehicle. If the code appears, it should be addressed promptly to prevent further damage.

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