AutoCodes – GMC – P0990 GMC

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

Quick Answer

The Transmission Fluid Pressure (TFP) switch 5 is part of the Transmission Control Solenoid Valve Assembly, which has no serviceable parts. Common causes include Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve Assembly. 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 Low transmission fluid level, Dirty transmission fluid, Faulty Transmission Control Solenoid Valve Assembly.
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 653

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 Mar 25, 2024

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0990 GMC Description

The Transmission Fluid Pressure (TFP) switch 5 is part of the Transmission Control Solenoid Valve Assembly, which has no serviceable parts. The Transmission Control Module (TCM) supplies a signal circuit to the TFP switch 5. The TFP switch 5 has an internal case ground. TFP switch 5 is normally closed or LOW. When oil pressure is present at the TFP switch 5, the switch is open or HIGH. The normally high pressure control (PC) solenoid 3 controls pressure to the R1/4-5-6 clutch regular valve. The TCM monitors the TFP switch 5 signal circuit to determine the position of the R1/4-5-6 clutch regulator valve. When the low and reverse clutch and 4-5-6 clutch are commanded OFF, pressure is present on the TFP switch 5. When the low and reverse clutch or the 4-5-6 clutch is commanded ON, the R1/4-5-6 clutch regulator valve moves and pressure to the TFP switch 5 is exhausted through the R1/4-5-6 clutch regulator valve. The Diagnostic Trouble Code (DTC) will be set when the TCM detects that the TFP switch 5 signal voltage remains HIGH after the 4-5-6 clutch transitions from a LOW pressure state to a HIGH pressure state. The TCM counts each incident. The DTC sets when 15 counts are accumulated.

OBDII Code P0990 GMC - Transmission Fluid Pressure Switch 5 Circuit High Voltage - AutoCodes.com — P0990 GMC Code - Transmission Fluid Pressure Switch 5 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0990 GMC?

Low transmission fluid level
Dirty transmission fluid
Faulty Transmission Control Solenoid Valve Assembly
Transmission Control Solenoid Valve Assembly harness is open or shorted
Transmission Control Solenoid Valve Assembly circuit poor electrical connection

How to Fix the DTC P0990 GMC?

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 P0990 GMC 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 P0990 GMC code?

Need more information on how to fix the P0990 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0990 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P0990 2014 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit High Voltage
P0990 2015 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit High Voltage
P0990 2016 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit High Voltage
P0990 2017 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit High Voltage
P0990 2018 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit High Voltage

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.