AutoCodes – Toyota – P0731 Toyota

P0731 Toyota Code - Gear 1 Incorrect Ratio

Quick Answer

This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows: Torque converter slip ratio = A x C/B A: Output shaft revolution signal from revolution sensor B: Engine speed signal from Engine Control Module (ECM) C: Gear ratio determined as gear position which TCM supposes If the actual gear position is higher than the position (1st) supposed by TCM, the slip ratio will be more than normal. Common causes include Low transmission fluid level, Dirty transmission fluid, Shift solenoids. 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: P0731 Toyota indicates Gear 1 Incorrect Ratio.
Common causes: Common causes include Low transmission fluid level, Dirty transmission fluid, Shift solenoids.
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 5,698

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 Jun 14, 2020

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0731 Toyota Description

This diagnosis monitors actual gear position by checking the torque converter slip ratio calculated by Transmission Control Module (TCM) as follows:

Torque converter slip ratio = A x C/B
A: Output shaft revolution signal from revolution sensor
B: Engine speed signal from Engine Control Module (ECM)
C: Gear ratio determined as gear position which TCM supposes

If the actual gear position is higher than the position (1st) supposed by TCM, the slip ratio will be more than normal. In case the ratio exceeds the specified value, TCM judges this diagnosis malfunction.

OBDII Code P0731 Toyota - Gear 1 Incorrect Ratio - AutoCodes.com — P0731 Toyota Code - Gear 1 Incorrect Ratio

What does this mean?

What are the Possible Causes of the DTC P0731 Toyota?

Low transmission fluid level
Dirty transmission fluid
Shift solenoids
Transmission mechanical problems
Transmission hydraulic control circuit

How to Fix the DTC P0731 Toyota?

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 does this mean?

Code Tech Notes

Start by inspecting the transmission fluid level and condition, and change fluid if necessary.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0731 Toyota 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.

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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 P0731 Toyota Code

1. What does the OBDII code P0731 mean on a Toyota?

Code P0731 on a Toyota indicates "Gear 1 Incorrect Ratio," meaning the transmission control module (TCM) has detected an issue with the gear ratio in first gear.

2. What are the common symptoms of code P0731 in a Toyota?

Common symptoms include difficulty shifting into or out of first gear, slipping in first gear, reduced acceleration, harsh shifting, or the check engine light turning on.

3. What causes the P0731 code on a Toyota?

Possible causes include low or dirty transmission fluid, a malfunctioning solenoid, a faulty speed sensor, worn clutches or bands in the transmission, or internal transmission damage.

4. Can driving with code P0731 damage my Toyota?

Yes, driving with this code may cause further damage to the transmission if the issue is not resolved promptly, potentially leading to costly repairs.

5. How do I fix the P0731 code on my Toyota?

Repairs may include checking and replacing the transmission fluid, replacing a defective solenoid or speed sensor, or addressing internal transmission issues like worn clutches or bands.

6. How is code P0731 diagnosed in a Toyota?

A mechanic will use a scan tool to check for other related codes, inspect the transmission fluid, test the solenoids and sensors, and may perform a transmission pressure test or teardown if needed.

7. Can low transmission fluid cause code P0731 in a Toyota?

Yes, low or contaminated transmission fluid can disrupt proper gear operation and lead to the P0731 code being triggered.

8. How much does it cost to fix code P0731 in a Toyota?

The cost varies depending on the cause. Simple fixes like fluid replacement may cost $100â€“$200, while major repairs like rebuilding the transmission can cost $1,500â€“$3,000 or more.

9. Can a bad speed sensor trigger the P0731 code on a Toyota?

Yes, a faulty speed sensor can send incorrect signals to the transmission control module, leading to the P0731 code.

10. Is it safe to drive my Toyota with the P0731 code?

It is not recommended to drive with this code as it may worsen transmission issues or cause unsafe driving conditions. Have the vehicle inspected and repaired as soon as possible.