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P0990 2016 GMC Sierra Code - Transmission Fluid Pressure Switch 5 Circuit High Voltage

Quick Answer

The P0990 diagnostic trouble code (DTC) for a 2016 GMC Sierra relates to the Transmission Fluid Pressure Switch 5 Circuit High Voltage. Common causes include Faulty transmission fluid pressure switch, Damaged wiring or connectors in the circuit, Malfunctioning transmission control module (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
P0990 2016 GMC Sierra indicates Transmission Fluid Pressure Switch 5 Circuit High Voltage.
Common causes
Common causes include Faulty transmission fluid pressure switch, Damaged wiring or connectors in the circuit, Malfunctioning transmission control module (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.
What is this?
Table of contents Created and updated by William Orellana on Sep 16, 2024
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Code P0990 2016 GMC Sierra Description

The P0990 diagnostic trouble code (DTC) for a 2016 GMC Sierra relates to the Transmission Fluid Pressure Switch 5 Circuit High Voltage. This code indicates that there is an issue with the transmission fluid pressure switch circuit, specifically that the voltage is higher than normal. The transmission fluid pressure switch is a crucial component of the vehicle's transmission system, responsible for monitoring and regulating the fluid pressure to ensure smooth gear shifts and overall transmission performance.

OBDII Code P0990 2016 GMC Sierra - Transmission Fluid Pressure Switch 5 Circuit High Voltage
P0990 2016 GMC Sierra Code - Transmission Fluid Pressure Switch 5 Circuit High Voltage

Common Causes of P0990 2016 GMC Sierra

  1. Faulty transmission fluid pressure switch
  2. Damaged wiring or connectors in the circuit
  3. Malfunctioning transmission control module (TCM)
  4. Low or contaminated transmission fluid
  5. Electrical issues in the transmission system

Symptoms of P0990 2016 GMC Sierra

  1. Erratic gear shifts
  2. Harsh shifting
  3. Transmission slipping
  4. Transmission failing to engage
  5. Illumination of the Check Engine Light

How to Fix P0990 2016 GMC Sierra

  1. Begin by conducting a thorough diagnostic scan to confirm the P0990 code and identify the specific cause of the high voltage in the transmission fluid pressure switch circuit.
  2. Inspect the transmission fluid pressure switch, wiring, and connectors for any signs of damage or corrosion. Replace any faulty components as needed.
  3. Check the transmission fluid level and condition. If low or contaminated, perform a transmission fluid flush and refill with the manufacturer-recommended fluid.
  4. Test the transmission control module (TCM) for proper operation and replace if necessary.
  5. Clear the DTC and test drive the vehicle to ensure that the transmission is operating correctly and the code does not reappear.

Cost to Fix P0990 2016 GMC Sierra

The typical repair costs for addressing the P0990 code on a 2016 GMC Sierra can vary depending on the specific cause of the issue and the extent of the repairs needed. In general, the cost of parts for replacing the transmission fluid pressure switch or repairing wiring/connectors can range from $100 to $300. Labor costs at an auto repair shop can add an additional $100 to $300, with total repair costs potentially amounting to $200 to $600.

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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 P0990 2016 GMC Sierra Code

1. What does the OBDII code P0990 mean on a 2016 GMC Sierra?

P0990 indicates a high voltage issue in the Transmission Fluid Pressure (TFP) Switch 5 Circuit, which helps monitor hydraulic pressure in the transmission.

2. What are the common symptoms of code P0990 in a 2016 GMC Sierra?

Symptoms may include erratic shifting, the transmission stuck in a single gear, reduced power mode, delayed engagement, or the check engine light turning on.

3. What causes the P0990 code to appear on a 2016 GMC Sierra?

Common causes include a faulty pressure switch, damaged wiring or connectors in the circuit, a malfunctioning transmission control module (TCM), or low transmission fluid.

4. Can low transmission fluid cause the P0990 code?

Yes, low or contaminated transmission fluid can lead to improper hydraulic pressure, triggering the P0990 code.

5. How do you diagnose the P0990 code in a 2016 GMC Sierra?

Start by checking the transmission fluid level and condition, inspecting the wiring and connectors for damage, and testing the TFP switch and related circuits with a multimeter.

6. Is it safe to drive a 2016 GMC Sierra with the P0990 code?

Driving with this code is not recommended as it can lead to poor transmission performance or potential damage if the issue is not resolved.

7. How much does it cost to fix the P0990 code on a 2016 GMC Sierra?

Repair costs can vary, but replacing the TFP switch typically costs $150–$300, while wiring repairs or TCM replacement may cost more depending on labor rates.

8. Can the P0990 code be caused by a bad transmission control module (TCM)?

Yes, a malfunctioning TCM can misinterpret circuit voltage levels and trigger the P0990 code.

9. Will clearing the P0990 code fix the issue on a 2016 GMC Sierra?

Clearing the code with a scanner will temporarily turn off the check engine light, but the underlying issue must be addressed to prevent the code from returning.

10. How do you prevent the P0990 code from occurring?

Regular maintenance, such as checking and replacing transmission fluid, inspecting wiring for damage, and addressing transmission issues promptly, can help prevent this code.

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