AutoCodes – GMC – P0873 2017 GMC Sierra

P0873 2017 GMC Sierra Code - Transmission Fluid Pressure Switch 3 Circuit High Voltage

Quick Answer

The transmission fluid pressure switch, also known as the pressure switch manifold, is a multiple switch assembly made up of 3 normally open pressure switches and 1 normally closed pressure switch. 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: P0873 2017 GMC Sierra indicates Transmission Fluid Pressure Switch 3 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 542

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

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Table of contents Created and updated by William Orellana on Aug 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0873 2017 GMC Sierra Description

The transmission fluid pressure switch, also known as the pressure switch manifold, is a multiple switch assembly made up of 3 normally open pressure switches and 1 normally closed pressure switch. Pressure switch 1 monitors shift valve 1 positioning, pressure switch 2 monitors shift valve 2 positioning, pressure switch 3 monitors shift valve 3 positioning, and pressure switch 4 monitors the position of the manual selector valve. The TCM provides a signal circuit to each of the pressure switches. The TCM constantly monitors the circuits to determine the position of the shift valves. The position of shift valves 1, 2, and 3 is controlled by 3 normally closed shift solenoids. When energized, shift solenoid 1 directs fluid pressure to shift valve 1, shift solenoid 2 directs fluid pressure to shift valve 2, and shift solenoid 3 directs fluid pressure to shift valve 3, which strokes the shift valves. When a shift valve is stroked, an exhaust passage is blocked and fluid pressure increases, closing the normally open pressure switch. The Diagnostic Trouble Code (DTC) will be set when the TCM detects that transmission fluid pressure switch 3 signal circuit is High when shift solenoid 3 is commanded ON for 1 s.

OBDII Code P0873 2017 GMC Sierra - Transmission Fluid Pressure Switch 3 Circuit High Voltage - AutoCodes.com — P0873 2017 GMC Sierra Code - Transmission Fluid Pressure Switch 3 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0873 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
Faulty Transmission Control Module (TCM)

How to Fix the DTC P0873 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 P0873 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 P0873 2017 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 P0873 2017 GMC Sierra Code

1. What does the OBDII code P0873 mean on a 2017 GMC Sierra?

P0873 indicates that the Transmission Control Module (TCM) has detected a high voltage issue in the Transmission Fluid Pressure Switch 3 Circuit.

2. What are the symptoms of code P0873 on a 2017 GMC Sierra?

Common symptoms include harsh or delayed shifting, the transmission going into limp mode, and the illumination of the check engine light.

3. What causes the P0873 code on a 2017 GMC Sierra?

Possible causes include a faulty transmission fluid pressure switch, damaged wiring or connectors in the circuit, low or dirty transmission fluid, or a malfunctioning TCM.

4. Can driving with a P0873 code cause further damage?

Yes, driving with this code can lead to further transmission issues or damage, especially if the transmission is in limp mode or shifting improperly.

5. How do you diagnose the P0873 code on a 2017 GMC Sierra?

Diagnosis involves inspecting the wiring and connectors for damage, checking the transmission fluid level and condition, and using a scan tool to monitor the transmission pressure sensor readings.

6. How do you fix the P0873 code on a 2017 GMC Sierra?

Repairs may include replacing the transmission fluid pressure switch, repairing damaged wiring or connectors, performing a transmission fluid change, or reprogramming or replacing the TCM if necessary.

7. Could a low transmission fluid level trigger the P0873 code?

Yes, low transmission fluid can cause inaccurate pressure readings, potentially triggering the P0873 code.

8. How much does it cost to repair the P0873 code on a 2017 GMC Sierra?

The cost varies depending on the issue, ranging from $50 to $200 for simple fixes like wiring repairs or fluid changes, to over $500 if the pressure switch or TCM needs replacement.

9. Can a bad transmission fluid pressure switch cause other transmission problems?

Yes, a faulty switch can lead to incorrect pressure readings, affecting shift timing, gear engagement, and overall transmission performance.

10. Is clearing the P0873 code enough to fix the problem?

No, clearing the code without addressing the underlying issue may result in the code returning and further transmission issues. Always diagnose and repair the root cause.