AutoCodes – Buick – P0990 Buick

P0990 Buick 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 Buick 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 973

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

What does this mean?

What are the Possible Causes of the DTC P0990 Buick?

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 Buick?

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 Buick 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 Buick code?

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

Need Help with the Code?

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

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 Buick Code

1. What are the common symptoms of OBDII code P0990 in a Buick related to the Transmission Fluid Pressure Switch 5 Circuit High Voltage?

The common symptoms may include harsh shifting, transmission slipping, and the transmission going into limp mode.

2. What are some possible causes of OBDII code P0990 in a Buick?

Potential causes of this code can include a faulty transmission fluid pressure switch, wiring or connector issues, low transmission fluid level, or a malfunctioning transmission control module.

3. How can I diagnose the issue causing OBDII code P0990 in my Buick?

A thorough diagnostic process may involve checking the transmission fluid level and condition, inspecting the wiring and connectors related to the transmission fluid pressure switch, and using a scan tool to monitor the switch's operation.

4. Can driving with OBDII code P0990 in a Buick cause further damage to the vehicle?

Continuing to drive with this code may lead to further transmission issues and potentially cause damage to other components, so it is advisable to address the problem promptly.

5. What are some repair tips for resolving OBDII code P0990 in a Buick?

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

6. Is it safe to continue driving my Buick with OBDII code P0990 present?

It is not recommended to continue driving the vehicle with this code as it could lead to further transmission problems and potentially compromise safety and drivability.

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

The cost of repairing this code can vary depending on the specific issue causing it, but it may involve parts and labor costs ranging from $200 to $500 or more.

8. Can OBDII code P0990 be triggered intermittently in a Buick?

Yes, this code can sometimes be triggered intermittently, especially if the issue is related to a loose connection or a faulty sensor that only malfunctions under certain conditions.

9. Will resetting the trouble codes make OBDII code P0990 disappear permanently in a Buick?

Simply resetting the trouble codes may temporarily clear the code, but if the underlying issue causing P0990 is not addressed, the code is likely to reappear upon driving the vehicle.

10. How urgent is it to address OBDII code P0990 in a Buick?

It is recommended to address this code as soon as possible to prevent potential transmission damage and ensure the safe and reliable operation of your vehicle.