AutoCodes – Infiniti – P1731 Infiniti

P1731 Infiniti Code - A/T 1st Engine Braking

Quick Answer

The engine braking is controlled by the Low Coast Brake Solenoid Valve. Common causes include Low transmission fluid, Faulty Low Coast Brake Solenoid Valve, Low Coast Brake Solenoid Valve 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: P1731 Infiniti indicates A/T 1st Engine Braking.
Common causes: Common causes include Low transmission fluid, Faulty Low Coast Brake Solenoid Valve, Low Coast Brake Solenoid Valve 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 13,324

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 03, 2020

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code P1731 Infiniti Description

The engine braking is controlled by the Low Coast Brake Solenoid Valve. The Transmission Control Module (TCM) uses the Automatic Transmission Fluid (ATF) Pressure Switch to monitor the Low Coast Brake apply pressure. The Diagnostic Trouble Code (DTC) will set when the TCM monitors each ATF Pressure Switch and Low Coast Brake Solenoid monitor value and detects as irregular when engine brake of 1st gear acts other than at M1 position.

OBDII Code P1731 Infiniti - A/T 1st Engine Braking - AutoCodes.com — P1731 Infiniti Code - A/T 1st Engine Braking

What does this mean?

What are the Possible Causes of the DTC P1731 Infiniti?

Low transmission fluid
Faulty Low Coast Brake Solenoid Valve
Low Coast Brake Solenoid Valve harness is open or shorted
Low Coast Brake Solenoid Valve circuit poor electrical connection
Faulty Automatic Transmission Fluid (ATF) Pressure Switch

How to Fix the DTC P1731 Infiniti?

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 P1731 Infiniti 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 P1731 Infiniti code?

Need more information on how to fix the P1731 Infiniti code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the P1731 Infiniti code diagnosed by a professional: Find a repair shop in your area

Information for Specific Infiniti Models

P1731 2003 Infiniti G35 — A/T 1st Engine Braking
P1731 2004 Infiniti G35 — A/T 1st Engine Braking
P1731 2005 Infiniti G35 — A/T 1st Engine Braking
P1731 2006 Infiniti G35 — A/T 1st Engine Braking

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 P1731 Infiniti Code

1. What does the OBDII code P1731 mean for an Infiniti?

P1731 indicates a problem with the automatic transmission's 1st gear engine braking system, often related to a hydraulic or electronic control issue.

2. What are the common symptoms of the P1731 code?

Symptoms may include harsh shifting, no engine braking in 1st gear, reduced transmission performance, or the check engine light being illuminated.

3. What causes the P1731 code to trigger in an Infiniti?

Common causes include a faulty valve body, a malfunctioning transmission solenoid, low or dirty transmission fluid, or internal transmission damage.

4. How can I diagnose the P1731 code on my Infiniti?

Start by checking the transmission fluid condition and level, inspect the wiring and connectors for damage, and use a scan tool to monitor solenoid operation and transmission gear data.

5. Can driving with the P1731 code cause further damage?

Yes, continuing to drive with this code can lead to additional transmission damage or unsafe driving conditions due to compromised gear operation.

6. How do I fix the P1731 code on an Infiniti?

Repairs may include replacing a faulty transmission solenoid, cleaning or replacing the valve body, flushing the transmission fluid, or addressing internal transmission issues.

7. Is the P1731 code specific to Infiniti vehicles?

While P1731 is commonly associated with Infiniti models, it may also appear in other vehicles using similar transmission systems.

8. How much does it cost to repair the P1731 code on an Infiniti?

Repair costs can range from $150 to $2,000, depending on the issue, such as replacing a solenoid or addressing internal transmission failure.

9. Can low transmission fluid cause the P1731 code?

Yes, low or dirty transmission fluid can affect hydraulic pressure and solenoid function, potentially triggering the P1731 code.

10. Do I need a professional mechanic to fix the P1731 code?

While basic checks like fluid inspection can be done at home, diagnosing and repairing transmission issues often require specialized tools and expertise.