P0743

Torque Converter Clutch Solenoid Circuit Electrical

Car Fault Codes Transmission

Can you still drive? With care, short trips only

Who can fix it? Needs a workshop

Typical repair time 30 minutes – 5 hours

Typical cost SAR 100 to 2,500

What it means

The transmission control module (TCM) has detected electrical values in the torque converter clutch solenoid circuit that make no sense, such as a short to ground or to power, or incorrect resistance. The computer usually disables converter lockup until the fault is repaired.

Symptoms5

Engine speed higher than usual on the highway.
Higher fuel consumption.
Check engine light on.
Higher transmission fluid temperature on long trips.
With some shorts, lockup may stay applied and the engine may lug at a stop.

Possible causes6

Internal short in the solenoid coil.
Chafed wire touching the body or another power wire.
Corroded transmission connector, or oil or water inside it.
Damaged internal wiring harness inside the transmission.
Power or ground problem at the transmission computer.
Fault in the driver circuit inside the computer (less common).

How to diagnose5

Read all codes and record freeze frame data to see when the code set.
Measure solenoid coil resistance and compare it with the manufacturer specification; very low means a short, very high means an open.
With connectors unplugged, check the circuit for shorts to ground and to power with a multimeter.
Inspect the connector and external harness for chafing or corrosion.
Check the computer power and ground before condemning the computer.

How to fix6

Clean the connector, repair its pins or replace its seal.
Repair the chafed wire and re-route the harness away from sharp or hot parts.
Replace the torque converter clutch solenoid if its resistance is out of specification.
Replace the internal harness if it is damaged.
Repair the computer power or ground, and reprogram or replace the computer if it is proven faulty.
Clear the codes, then road test and confirm lockup works and the code does not return.

Repair cost

0–500

500–2,000

2,000–5,000

5,000+

In Saudi riyals; the highlighted part is the expected range for this fault.

The cost is low when a wire or external connector is at fault, and rises when the solenoid or internal harness must be replaced inside the transmission or the computer needs repair.

Prices are rough estimates for common cars at independent workshops and vary with the car and the source of the part.
Prices last updated: September 2026

Frequently asked questions

What is the difference between P0743 and P0740?

Both are electrical, but P0743 usually covers shorts and wrong resistance rather than only an open circuit. Naming varies between manufacturers, so both are tested in much the same way.

Can a short damage the transmission computer?

A lasting short can strain the driver circuit inside the computer, so fix the cause of the short before fitting a new solenoid or computer, or the damage may repeat.

This guide is for information only and does not replace an inspection by a qualified technician. If the fault involves brakes, steering, engine temperature, electrics or refrigerant, do not attempt the repair yourself.

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