AutoCodes – Generic – P1784

P1784 Code - L-R Pressure Switch Circuit

Quick Answer

The Transmission Control Module (TCM) monitors the Solenoid/Pressure Switch Assembly. Common causes include Low battery voltage, Faulty Solenoid/Pressure Switch Assembly, Solenoid/Pressure Switch Assembly harness is open or shorted. 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: P1784 indicates L-R Pressure Switch Circuit.
Common causes: Common causes include Low battery voltage, Faulty Solenoid/Pressure Switch Assembly, Solenoid/Pressure Switch Assembly harness is open or shorted.
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 39,821

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 Feb 10, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
Comments
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Code P1784 Description

The Transmission Control Module (TCM) monitors the Solenoid/Pressure Switch Assembly. The Diagnostic Trouble Code (DTC) P1784 will set if low-reverse pressure switch is opened or closed at the incorrect time in a given gear.

OBDII Code P1784 - L-R Pressure Switch Circuit - AutoCodes.com — P1784 Code - L-R Pressure Switch Circuit

What does this mean?

What are the Possible Causes of the DTC P1784?

Low battery voltage
Faulty Solenoid/Pressure Switch Assembly
Solenoid/Pressure Switch Assembly harness is open or shorted
Solenoid/Pressure Switch Assembly circuit poor electrical connection
Faulty Transmission Control Module (TCM)

How to Fix the DTC P1784?

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 P1784 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 P1784 code?

Need more information on how to fix the P1784 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1784 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

P1784 Chrysler — L-R Pressure Switch Circuit
P1784 Dodge — L-R Pressure Switch Circuit
P1784 Ford — Transmission System First or Reverse Gear Fault Conditions
P1784 Jeep — L-R Pressure Switch Circuit
P1784 RAM — L-R Pressure Switch Circuit

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.