AutoCodes – Chevrolet – P0990 2018 Chevrolet Silverado

P0990 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado 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 425

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
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Code P0990 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado - Transmission Fluid Pressure Switch 5 Circuit High Voltage - AutoCodes.com — P0990 2018 Chevrolet Silverado Code - Transmission Fluid Pressure Switch 5 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0990 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado?

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 2018 Chevrolet Silverado 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 2018 Chevrolet Silverado code?

Need more information on how to fix the P0990 2018 Chevrolet Silverado code? Get Access to Factory Service Manuals

Need Help with the Code?

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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 2018 Chevrolet Silverado Code

What does the OBDII code P0990 mean for a 2018 Chevrolet Silverado?

Code P0990 indicates "Transmission Fluid Pressure Switch 5 Circuit High Voltage," which means an electrical issue has been detected in the pressure switch circuit of the transmission.

What are common symptoms of code P0990 in a 2018 Chevrolet Silverado?

Symptoms may include erratic shifting, failure to shift gears, transmission slipping, or an illuminated check engine light.

What causes code P0990 to appear on a 2018 Chevrolet Silverado?

Possible causes include a faulty transmission fluid pressure switch, damaged wiring or connectors in the circuit, or issues with the transmission control module (TCM).

Can driving with code P0990 damage my 2018 Chevrolet Silverado?

Yes, driving with this code can lead to further damage to the transmission, reduced performance, or unsafe driving conditions. Addressing the issue promptly is recommended.

How do I diagnose code P0990 on a 2018 Chevrolet Silverado?

Diagnosis typically involves using an OBDII scanner, inspecting the pressure switch and its wiring for damage, and testing the circuit for high voltage signals.

Can a faulty transmission fluid pressure switch cause code P0990?

Yes, a malfunctioning or stuck pressure switch is a common cause of this code and should be inspected during diagnostics.

How can I fix code P0990 on a 2018 Chevrolet Silverado?

Repairs may include replacing the pressure switch, repairing or replacing damaged wiring, or reprogramming the transmission control module if necessary.

Does code P0990 always require replacing the transmission fluid pressure switch?

Not always. The issue could also stem from wiring problems, connector issues, or a malfunctioning TCM, so proper diagnostics are essential.

What tools are needed to fix code P0990 on a 2018 Chevrolet Silverado?

You may need an OBDII scanner, a multimeter for testing voltage, and basic tools for inspecting and repairing wiring or connectors.

Can a low transmission fluid level cause code P0990?

Low transmission fluid typically causes different codes, but ensuring proper fluid levels is always a good first step in diagnosing transmission-related issues.