AutoCodes – GMC – P0848 2018 GMC Sierra

P0848 2018 GMC Sierra Code - Transmission Fluid Pressure Switch 2 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: P0848 2018 GMC Sierra indicates Transmission Fluid Pressure Switch 2 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 207

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 Aug 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P0848 2018 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 2 signal circuit is High when shift solenoid 2 is commanded ON for 1 s.

OBDII Code P0848 2018 GMC Sierra - Transmission Fluid Pressure Switch 2 Circuit High Voltage - AutoCodes.com — P0848 2018 GMC Sierra Code - Transmission Fluid Pressure Switch 2 Circuit High Voltage

What does this mean?

What are the Possible Causes of the DTC P0848 2018 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 P0848 2018 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 P0848 2018 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 P0848 2018 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 P0848 2018 GMC Sierra Code

1. What does the OBDII code P0848 mean on a 2018 GMC Sierra?

P0848 indicates a high voltage issue in the transmission fluid pressure switch 2 circuit, which monitors hydraulic pressure within the transmission.

2. What are the common symptoms of code P0848 in a 2018 GMC Sierra?

Symptoms may include erratic shifting, the transmission stuck in a single gear (limp mode), illuminated check engine light, and decreased fuel efficiency.

3. What causes the P0848 code to appear in a 2018 GMC Sierra?

Common causes include a faulty transmission fluid pressure switch, damaged or corroded wiring, connector issues, or a malfunctioning transmission control module (TCM).

4. Can a low transmission fluid level trigger the P0848 code?

No, the P0848 code specifically relates to an electrical issue in the pressure switch circuit, not fluid level, though low fluid can cause other transmission problems.

5. How is the P0848 code diagnosed in a 2018 GMC Sierra?

A mechanic will use a scan tool to confirm the code, inspect wiring and connectors, test the transmission fluid pressure switch, and check for proper voltage and continuity in the circuit.

6. Can I drive my 2018 GMC Sierra with the P0848 code active?

Driving with the P0848 code is not recommended, as it may cause further damage to the transmission or lead to unsafe driving conditions.

7. How do you fix the P0848 code on a 2018 GMC Sierra?

Repairs may include replacing the transmission fluid pressure switch, repairing or replacing damaged wiring, cleaning corroded connectors, or reprogramming the TCM if needed.

8. How much does it cost to repair the P0848 code on a GMC Sierra?

The repair cost depends on the underlying issue, but replacing a pressure switch typically costs between $100 and $300, including parts and labor.

9. Can a software update resolve the P0848 code in a 2018 GMC Sierra?

In some cases, a TCM software update may fix the issue if the fault is due to a programming glitch, though this is less common.

10. What tools are needed to troubleshoot the P0848 code on a 2018 GMC Sierra?

Diagnosing this code typically requires a scan tool, a multimeter for testing voltage and continuity, and potentially wiring diagrams for the transmission circuit.