AutoCodes – GMC – P0989 2016 GMC Sierra

P0989 2016 GMC Sierra Code - Transmission Fluid Pressure Switch 5 Circuit Low 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: P0989 2016 GMC Sierra indicates Transmission Fluid Pressure Switch 5 Circuit Low 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 500

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 P0989 2016 GMC Sierra 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 LOW after the 4-5-6 clutch transitions from a HIGH pressure state to a LOW pressure state. The TCM counts each incident. The DTC sets when 18 counts are accumulated.

OBDII Code P0989 2016 GMC Sierra - Transmission Fluid Pressure Switch 5 Circuit Low Voltage - AutoCodes.com — P0989 2016 GMC Sierra Code - Transmission Fluid Pressure Switch 5 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0989 2016 GMC Sierra?

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 P0989 2016 GMC Sierra?

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 P0989 2016 GMC Sierra 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 P0989 2016 GMC Sierra code?

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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 P0989 2016 GMC Sierra Code

1. What does the OBDII code P0989 mean on a 2016 GMC Sierra?

The P0989 code indicates "Transmission Fluid Pressure Switch 5 Circuit Low Voltage," meaning the transmission control module (TCM) is detecting a low voltage issue in the circuit of pressure switch 5.

2. What are the common symptoms of the P0989 code in a 2016 GMC Sierra?

Symptoms may include harsh or delayed shifting, transmission slipping, poor acceleration, the transmission going into limp mode, and an illuminated check engine light.

3. What causes the P0989 code to appear on a 2016 GMC Sierra?

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

4. Can low transmission fluid cause the P0989 code on a 2016 GMC Sierra?

Yes, low or contaminated transmission fluid can lead to improper pressure readings, potentially triggering the P0989 code.

5. How do you diagnose the P0989 code in a 2016 GMC Sierra?

Diagnosis involves scanning for additional codes, inspecting the wiring and connectors to the pressure switch, testing the switch itself, and checking the transmission fluid level and condition.

6. Can I drive my 2016 GMC Sierra with the P0989 code?

Driving with the P0989 code is not recommended, as it can lead to further transmission damage or unsafe driving conditions due to shifting issues.

7. How is the P0989 code fixed on a 2016 GMC Sierra?

Repairs may include replacing the faulty pressure switch, repairing damaged wiring or connectors, topping off or flushing the transmission fluid, or reprogramming or replacing the TCM.

8. How much does it cost to fix the P0989 code on a 2016 GMC Sierra?

Repair costs vary but can range from $150 to $400 for pressure switch replacement, while more complex issues like TCM replacement may cost $500 or more.

9. Can a faulty TCM cause the P0989 code in a 2016 GMC Sierra?

Yes, a malfunctioning transmission control module can incorrectly interpret signals from the pressure switch, triggering the P0989 code.

10. How can I prevent the P0989 code from occurring in my 2016 GMC Sierra?

Regular maintenance such as checking transmission fluid levels, keeping the fluid clean, and inspecting wiring and connectors for damage can help prevent the P0989 code.