Engine-CodesGMC – P0990 GMC

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

Quick Answer

The P0990 code for GMC vehicles refers to an issue with the Transmission Fluid Pressure Switch 5 Circuit High Voltage. Common causes include Faulty transmission fluid pressure switch, Short circuit in the wiring harness, Corrosion or damage to electrical connectors. 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 GMC indicates Transmission Fluid Pressure Switch 5 Circuit High Voltage.
Common causes
Common causes include Faulty transmission fluid pressure switch, Short circuit in the wiring harness, Corrosion or damage to electrical connectors.
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.
Table of contents Created and updated by William Orellana on Sep 11, 2024
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Code P0990 GMC Description

The P0990 code for GMC vehicles refers to an issue with the Transmission Fluid Pressure Switch 5 Circuit High Voltage. This code indicates that there is a high voltage condition detected in the circuit responsible for controlling the transmission fluid pressure switch 5. The transmission fluid pressure switch plays a crucial role in regulating the transmission fluid pressure within the transmission system. When this switch malfunctions or detects a high voltage, it can lead to various performance issues and potential long-term damage to the transmission system.

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

Common Causes of P0990 GMC

  1. Faulty transmission fluid pressure switch
  2. Short circuit in the wiring harness
  3. Corrosion or damage to electrical connectors
  4. Low transmission fluid level
  5. Issues with the transmission control module

Symptoms of P0990 GMC

  1. Harsh or delayed shifting
  2. Slipping gears
  3. Transmission not engaging
  4. Check engine light illuminated
  5. Transmission overheating

How to Fix P0990 GMC

  1. Diagnose the issue using a scan tool to confirm the P0990 code and identify the specific cause.
  2. Inspect the transmission fluid pressure switch and wiring harness for any damage or corrosion.
  3. Replace the faulty transmission fluid pressure switch if necessary.
  4. Repair any damaged wiring or connectors in the circuit.
  5. Clear the code from the vehicle's computer and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0990 GMC

The typical repair costs for addressing a P0990 code can vary depending on the specific cause of the issue and the labor rates in your area. Generally, replacing a transmission fluid pressure switch and addressing any wiring issues can range from $200 to $500, including parts and labor. It's important to note that diagnostic time and labor rates at auto repair shops can vary, so it's advisable to check with local shops for a more accurate estimate based on your vehicle make and model. Additionally, rates may be higher at dealerships or metropolitan areas, while independent shops may offer more affordable prices.

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Information for Specific GMC Models

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 GMC Code

1. What are the common symptoms of OBDII code P0990 in a GMC vehicle?

- Common symptoms include transmission shifting issues, harsh shifting, reduced fuel efficiency, and the transmission going into limp mode.

2. What can cause the transmission fluid pressure switch 5 circuit high voltage error code P0990 in a GMC vehicle?

- Possible causes include a faulty transmission fluid pressure switch, wiring issues, a damaged connector, low transmission fluid level, or a malfunctioning transmission control module.

3. How can I diagnose the OBDII code P0990 related to the transmission fluid pressure switch in my GMC vehicle?

- Diagnosing this code typically involves checking the transmission fluid level, inspecting the wiring and connectors related to the pressure switch, and using a scan tool to monitor the switch's operation.

4. Can I continue driving my GMC vehicle with OBDII code P0990 present?

- It is not recommended to continue driving with this code present, as it can lead to further transmission damage and potential safety issues. It is best to address the underlying problem promptly.

5. What are the repair options for fixing OBDII code P0990 in a GMC vehicle?

- Repair options may include replacing the transmission fluid pressure switch, repairing any damaged wiring or connectors, ensuring the transmission fluid level is correct, and resetting the trouble code with a scan tool.

6. Will resetting the OBDII code P0990 in my GMC vehicle make the problem go away?

- Resetting the code may temporarily clear the error from the system, but if the underlying issue causing the high voltage in the transmission fluid pressure switch is not addressed, the code is likely to reappear.

7. How much does it typically cost to repair OBDII code P0990 in a GMC vehicle?

- The cost of repairing this code can vary depending on the specific cause of the issue, but it may range from $100 to $300 for parts and labor.

8. Is it possible to prevent OBDII code P0990 from occurring in my GMC vehicle?

- Regular maintenance, such as checking and maintaining proper transmission fluid levels, inspecting wiring harnesses for damage, and addressing any transmission issues promptly, can help prevent this code from occurring.

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