Engine-CodesGMC – P0873 2018 GMC Sierra

P0873 2018 GMC Sierra Code - Transmission Fluid Pressure Switch 3 Circuit High Voltage

Quick Answer

The P0873 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates a problem with the Transmission Fluid Pressure Switch 3 Circuit High Voltage. Common causes include Faulty Transmission Fluid Pressure Switch, Wiring issues or shorts in the circuit, Low transmission fluid levels. 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
P0873 2018 GMC Sierra indicates Transmission Fluid Pressure Switch 3 Circuit High Voltage.
Common causes
Common causes include Faulty Transmission Fluid Pressure Switch, Wiring issues or shorts in the circuit, Low transmission fluid levels.
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.
Table of contents Created and updated by William Orellana on Sep 14, 2024
💬 Need more help? Ask Auto Expert for instant answers — it's free!
AutoCodes App

Fix Your Car Smarter

Try the New AutoCodes App!

Get complete OBDII diagnostics, repair solutions, and cost estimates, plus AI chat support on demand.

AutoCodes App on Google Play

Code P0873 2018 GMC Sierra Description

The P0873 diagnostic trouble code (DTC) for a 2018 GMC Sierra indicates a problem with the Transmission Fluid Pressure Switch 3 Circuit High Voltage. This code is specifically related to the transmission system of the vehicle. The Transmission Fluid Pressure Switch is responsible for monitoring the hydraulic pressure within the transmission. When the switch detects that the pressure is too high, it triggers this code.

OBDII Code P0873 2018 GMC Sierra - Transmission Fluid Pressure Switch 3 Circuit High Voltage
P0873 2018 GMC Sierra Code - Transmission Fluid Pressure Switch 3 Circuit High Voltage

Common Causes of P0873 2018 GMC Sierra

  1. Faulty Transmission Fluid Pressure Switch
  2. Wiring issues or shorts in the circuit
  3. Low transmission fluid levels
  4. Contaminated transmission fluid
  5. Internal transmission problems

Symptoms of P0873 2018 GMC Sierra

  1. Harsh shifting between gears
  2. Slipping gears
  3. Transmission overheating
  4. Illumination of the Check Engine Light
  5. Decreased fuel efficiency

How to Fix P0873 2018 GMC Sierra

  1. Begin by diagnosing the specific cause of the high voltage in the Transmission Fluid Pressure Switch 3 Circuit.
  2. Inspect the wiring and connectors associated with the switch for any damage or corrosion.
  3. Check the transmission fluid level and quality, topping off or replacing as needed.
  4. Test the Transmission Fluid Pressure Switch for proper operation and replace if necessary.
  5. Clear the DTC and test drive the vehicle to ensure the issue has been resolved.

Cost to Fix P0873 2018 GMC Sierra

The cost of repairing a P0873 code on a 2018 GMC Sierra can vary depending on the specific cause of the issue. On average, the parts for this repair, including a new Transmission Fluid Pressure Switch, can range from $50 to $150. Labor costs at an auto repair shop can range from $80 to $150 per hour. Therefore, the total repair cost may fall between $150 to $400, including parts and labor. It is recommended to obtain quotes from local auto repair shops to get a more accurate estimate based on your location and vehicle specifics.

Need more information about the P0873 2018 GMC Sierra code?

Need more information on how to fix the P0873 2018 GMC Sierra code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P0873 2018 GMC Sierra 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 P0873 2018 GMC Sierra Code

1. What does the OBDII code P0873 mean on a 2018 GMC Sierra?

P0873 indicates that the Transmission Fluid Pressure Switch 3 Circuit is experiencing high voltage, which typically points to an issue with the pressure switch or its associated wiring.

2. What are the common symptoms of code P0873 in a 2018 GMC Sierra?

Symptoms may include erratic or harsh shifting, transmission slipping, the transmission being stuck in one gear, or the illumination of the check engine light.

3. What causes the P0873 code to appear on a 2018 GMC Sierra?

Common causes include a faulty transmission fluid pressure switch, damaged or corroded wiring or connectors in the circuit, low transmission fluid levels, or an internal transmission issue.

4. Can driving with a P0873 code damage my 2018 GMC Sierra?

Yes, driving with this code can potentially cause further damage to the transmission if the issue is not addressed promptly, especially if the transmission is slipping or shifting improperly.

5. How do you diagnose the P0873 code on a 2018 GMC Sierra?

Diagnosis involves scanning the vehicle with an OBDII scanner, inspecting the wiring and connectors for damage, testing the transmission fluid pressure switch, and checking the transmission fluid level and condition.

6. What repairs can fix the P0873 code on a 2018 GMC Sierra?

Repairs may include replacing the transmission fluid pressure switch, repairing or replacing damaged wiring or connectors, replenishing or flushing the transmission fluid, or addressing internal transmission issues.

7. Is low transmission fluid a possible cause of the P0873 code?

Yes, low or degraded transmission fluid can lead to improper pressure readings, which may trigger the P0873 code.

8. How much does it cost to fix the P0873 code on a 2018 GMC Sierra?

Repair costs can vary widely, with pressure switch replacement typically costing $100–$300 and more extensive transmission repairs costing significantly more.

9. Can a faulty transmission control module (TCM) cause the P0873 code?

While less common, a malfunctioning TCM can contribute to this code if it fails to interpret pressure switch signals correctly.

10. How can I prevent the P0873 code from recurring on my 2018 GMC Sierra?

Regularly maintain your transmission by checking fluid levels, using the recommended transmission fluid, and addressing wiring or connector issues promptly to prevent circuit malfunctions.

Discuss the causes and fixes for P0873 2018 GMC Sierra OBDII Code

Code P0873 2018 GMC Sierra comments

No comments found for this page.