AutoCodes – Subaru – P0743 Subaru

P0743 Subaru Code - Torque Converter Clutch Circuit Electrical

Quick Answer

The Torque Converter Clutch (TCC) is designed to increase efficiency by mechanically coupling the engine to the transmission. Common causes include Dirty transmission fluid, Low transmission fluid level, Faulty Torque Converter Clutch (TCC) Solenoid Valve. 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: P0743 Subaru indicates Torque Converter Clutch Circuit Electrical.
Common causes: Common causes include Dirty transmission fluid, Low transmission fluid level, Faulty Torque Converter Clutch (TCC) Solenoid Valve.
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 17,255

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 Dec 27, 2021

Description
Step-by-Step Diagnostic Guide
Possible Causes
How To Fix
Tech Notes
Cost to Diagnose
FAQs
Comments
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Code P0743 Subaru Description

The Torque Converter Clutch (TCC) is designed to increase efficiency by mechanically coupling the engine to the transmission. The TCC solenoid valve is activated, with the gear in D4, by the Transmission Control Module (TCM) in response to signals sent from the vehicle speed and the Engine Control Module (ECM). Lock-up piston operation will then be controlled. When the torque converter clutch solenoid valve is activated, the torque converter lockup clutch will engage creating a 1 to 1 RPM ratio between the transmission input shaft and the rotational speed of the torque converter. The lock-up operation, however, is prohibited when A/T fluid temperature is too low. When the accelerator pedal is depressed (less than 2/8) in lock-up condition, the engine speed should not change abruptly. If there is a big jump in engine speed, there is no lock-up. By performing a voltage drop test, the ECM detects that the Torque Converter Clutch (TCC) solenoid circuit is open or shorted and sets the Diagnostic Trouble Code (DTC).

OBDII Code P0743 Subaru - Torque Converter Clutch Circuit Electrical - AutoCodes.com — P0743 Subaru Code - Torque Converter Clutch Circuit Electrical

What does this mean?

What are the Possible Causes of the DTC P0743 Subaru?

Dirty transmission fluid
Low transmission fluid level
Faulty Torque Converter Clutch (TCC) Solenoid Valve
Torque Converter Clutch Solenoid Valve harness is open or shorted
Torque Converter Clutch Solenoid Valve circuit poor electrical connection

How to Fix the DTC P0743 Subaru?

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

This is an electrical problem code. Could be a problem with the harness to the Torque Converter Clutch (TCC) solenoid, the TCC solenoid connector, or the TCC solenoid itself.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the P0743 Subaru 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 P0743 Subaru Code

1. What are the common symptoms of OBDII code P0743 in a Subaru related to the Torque Converter Clutch Circuit Electrical?

The common symptoms include erratic shifting, transmission slipping, engine stalling at stops, and decreased fuel efficiency.

2. What are the possible causes of OBDII code P0743 in a Subaru?

The code P0743 in a Subaru is commonly caused by a faulty torque converter clutch solenoid, damaged wiring or connectors in the circuit, low transmission fluid level, or a malfunctioning torque converter.

3. How serious is OBDII code P0743 in a Subaru?

OBDII code P0743 related to the Torque Converter Clutch Circuit Electrical is a serious issue as it can lead to transmission problems, reduced fuel efficiency, and potential damage if left unaddressed.

4. Can I continue driving my Subaru with OBDII code P0743?

It is not recommended to continue driving your Subaru with OBDII code P0743 as it can cause further damage to the transmission and other components. It is advisable to have the issue diagnosed and repaired promptly.

5. How can I diagnose OBDII code P0743 in my Subaru?

Diagnosing OBDII code P0743 involves using a scan tool to read the code, checking the transmission fluid level and condition, inspecting the wiring and connectors related to the torque converter clutch circuit, and testing the torque converter clutch solenoid.

6. What are some repair tips for fixing OBDII code P0743 in a Subaru?

Repairing OBDII code P0743 may involve replacing the torque converter clutch solenoid, repairing or replacing damaged wiring or connectors, ensuring the transmission fluid is at the correct level and condition, and testing the torque converter for proper operation.

7. How much does it cost to repair OBDII code P0743 in a Subaru?

The cost of repairing OBDII code P0743 in a Subaru can vary depending on the exact cause of the issue, labor rates in your area, and whether any parts need to be replaced. It is recommended to get a few quotes from reputable mechanics.

8. Can OBDII code P0743 in a Subaru be caused by other underlying issues?

Yes, OBDII code P0743 in a Subaru can sometimes be triggered by other underlying issues such as a faulty transmission control module, internal transmission problems, or a damaged engine sensor. It is important to conduct a thorough diagnosis to identify the root cause.

9. How long does it typically take to repair OBDII code P0743 in a Subaru?

The time it takes to repair OBDII code P0743 in a Subaru can vary depending on the exact cause of the issue, the availability of parts, and the workload of the repair shop. In general, it may take a few hours to a day to complete the repair.

10. Can I reset the OBDII code P0743 in my Subaru myself?

You can reset the OBDII code P0743 in your Subaru using an OBDII scanner or by disconnecting the car's battery for a few minutes. However, it is important to note that simply resetting the code will not fix the underlying issue causing the code to appear. It is recommended to diagnose and repair the problem first.