AutoCodes – GMC – P0989 GMC

P0989 GMC 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 GMC 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 3,032

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

What does this mean?

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

Need more information on how to fix the P0989 GMC code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0989 GMC code diagnosed by a professional: Find a repair shop in your area

Information for Specific GMC Models

P0989 2014 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit Low Voltage
P0989 2015 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit Low Voltage
P0989 2016 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit Low Voltage
P0989 2017 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit Low Voltage
P0989 2018 GMC Sierra — Transmission Fluid Pressure Switch 5 Circuit Low 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 P0989 GMC Code

1. What are the common symptoms of OBDII code P0989 GMC?

The common symptoms of OBDII code P0989 GMC include harsh shifting, transmission slipping, decreased fuel efficiency, and the transmission going into limp mode.

2. What causes the Transmission Fluid Pressure Switch 5 Circuit Low Voltage code P0989 in a GMC vehicle?

The P0989 code in a GMC vehicle is typically caused by a faulty transmission fluid pressure switch, damaged wiring or connectors, low transmission fluid level, or a malfunctioning transmission control module (TCM).

3. How serious is the P0989 OBDII code in a GMC vehicle?

The P0989 code should be addressed promptly as it can lead to transmission damage if left unresolved. Ignoring this code may result in further transmission issues and potential safety hazards.

4. Can I continue driving my GMC vehicle with OBDII code P0989 present?

It is not recommended to drive your GMC vehicle with the P0989 code active, as it can cause further damage to the transmission. It's best to address the issue as soon as possible to prevent costly repairs.

5. How can I diagnose and repair OBDII code P0989 in my GMC vehicle?

Diagnosing the P0989 code involves checking the transmission fluid level, inspecting the transmission fluid pressure switch and its circuit, and scanning the TCM for any related faults. Repairs may include replacing the pressure switch, repairing wiring/connectors, or resetting the TCM.

6. Is it possible to reset the OBDII code P0989 in a GMC vehicle without fixing the underlying issue?

While clearing the code may temporarily turn off the check engine light, it will not fix the underlying issue causing the P0989 code. It's essential to address the root cause of the problem to prevent further transmission issues.

7. How much does it cost to repair OBDII code P0989 in a GMC vehicle?

The cost of repairing the P0989 code in a GMC vehicle can vary depending on the cause of the issue, the parts needed for replacement, and labor costs. It's recommended to consult a professional mechanic for an accurate estimate.

8. Can a DIY enthusiast fix the P0989 code in a GMC vehicle?

While some DIY enthusiasts may have the skills to diagnose and repair the P0989 code, dealing with transmission issues can be complex. It's best to consult a professional mechanic with experience in transmission repairs to ensure the problem is properly addressed.

9. Will the P0989 code in a GMC vehicle reset itself after the issue is fixed?

After repairing the underlying issue causing the P0989 code, you may need to clear the code using an OBDII scanner to reset the check engine light. Once the repair is completed and the code is cleared, the system should reset itself.

10. How can I prevent OBDII code P0989 from occurring in my GMC vehicle?

To prevent the P0989 code from occurring, it's essential to perform regular maintenance on your vehicle, including checking the transmission fluid level, inspecting the transmission components, and addressing any issues promptly to avoid potential damage.