AutoCodes – GMC – P0989 2017 GMC Sierra

P0989 2017 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 2017 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 362

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 2017 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 2017 GMC Sierra - Transmission Fluid Pressure Switch 5 Circuit Low Voltage - AutoCodes.com — P0989 2017 GMC Sierra Code - Transmission Fluid Pressure Switch 5 Circuit Low Voltage

What does this mean?

What are the Possible Causes of the DTC P0989 2017 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 2017 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 2017 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 2017 GMC Sierra code?

Need more information on how to fix the P0989 2017 GMC Sierra 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 P0989 2017 GMC Sierra Code

1. What does the OBDII code P0989 mean on a 2017 GMC Sierra?

P0989 indicates a "Transmission Fluid Pressure Switch 5 Circuit Low Voltage," meaning the vehicle's transmission control module (TCM) has detected a low voltage signal from the pressure switch in the hydraulic circuit.

2. What are the common symptoms of code P0989 in a 2017 GMC Sierra?

Symptoms may include harsh or delayed shifting, the transmission stuck in one gear (limp mode), decreased fuel efficiency, and the check engine light being illuminated.

3. What causes the P0989 code to appear on a 2017 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 TCM.

4. Can low transmission fluid cause the P0989 code?

Yes, low or contaminated transmission fluid can affect pressure readings and trigger the P0989 code.

5. How can I diagnose the P0989 code on my 2017 GMC Sierra?

Diagnosis typically involves checking the transmission fluid level and condition, inspecting wiring and connectors for damage, testing the transmission fluid pressure switch, and using a scan tool to monitor live data.

6. Can I drive my 2017 GMC Sierra with the P0989 code?

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

7. How do I fix a P0989 code on a 2017 GMC Sierra?

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

8. How much does it cost to repair a P0989 code on a 2017 GMC Sierra?

Repair costs vary depending on the issue, but replacing a transmission fluid pressure switch typically costs $150â€“$300, while wiring repairs or TCM replacements may cost more.

9. Does the P0989 code mean the transmission is failing?

Not necessarily. While it indicates an issue with the transmission fluid pressure circuit, it could be caused by minor problems like low fluid or a faulty sensor rather than total transmission failure.

10. Can a software update fix the P0989 code on a 2017 GMC Sierra?

In some cases, a TCM software update may resolve issues related to this code, but it depends on the root cause. Consult a qualified technician for an accurate diagnosis.