P0743 code meaning
Torque Converter Clutch Circuit Electrical
Powertrain system Generic code P07xx codes Check engine light
What P0743 means
The torque converter clutch (lock-up) connects pump and turbine mechanically; a solenoid – on/off, pulse-width modulated or proportional – moves a control valve in the valve body. Slip is engine speed minus turbine speed. Manufacturers do not use P0740–P0744 uniformly: Ford uses P0740 for open, P0742 for short to ground and P0744 for short to power, and reports stuck on as P2758. P0743 is the collective electrical code for the converter clutch solenoid circuit – open, short to ground or to positive – detected by terminal voltage, driver feedback or current. Subaru flags it after 0.14 s and lights the MIL after two trips, Saab's 9-3 of 2003 above 1356 mA for 500 ms, Allison after 1.5 s; older Ford transmissions also use it. The clutch is switched off; Saab's Aisin boxes go into limp mode, Subaru does not.
P0743 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modePossible
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P0743
- Check engine light or transmission warning
- No lock-up: engine speed about 100–300 rpm higher when cruising
- Limp mode on some makes (Saab/Aisin)
Common causes of P0743
- Most likelyTransmission harness or pass-through connector (corrosion, chafing, oil in connector)
- Most likelySolenoid coil open or shorted
- PossibleInternal harness or mechatronic unit
- Less likelyDriver stage in the transmission or engine module
Check the most likely causes first. Replacing parts by guesswork is the most expensive way to clear a code.
Parts involved
Torque converter clutch solenoidTorque converterTransmission valve bodyTransmission control module
What each part of P0743 means
| P | Powertrain system: engine, fuel system, ignition, emissions and transmission. |
| 0 | Generic code: it means the same on every make (SAE standard). |
| 7 | Area: transmission. |
| 43 | The exact fault in that area. |
What to do next
- Note P0743 and any other codes stored with it: several codes together often point to one cause.
- Check for loose connectors and damaged wiring around the parts the code names.
- Check open recalls for your car: some faults are fixed for free by the dealer. Enter your VIN.
- Clear the code only after the repair. If it comes back, the fault is still there.
Buying a used car? Scan it for stored codes before you pay. A recently cleared memory can hide a problem.
Questions about P0743
What does P0743 mean?
P0743 means "Torque Converter Clutch Circuit Electrical". The torque converter clutch (lock-up) connects pump and turbine mechanically; a solenoid – on/off, pulse-width modulated or proportional – moves a control valve in the valve body. It is a generic code, so it means the same on every make.
Is it safe to drive with P0743?
Drive gently and only to a workshop. With P0743 the car can go into limp mode (reduced power) to protect itself.
Will P0743 fail an emissions test?
Yes, it can. P0743 is emissions-related, so most inspection programs fail a car while it is stored or while the check engine light is on.
How hard is P0743 to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P0743 clear itself after the repair?
After the repair the car has to complete a drive cycle (a mix of city and highway driving) before the test runs again. Until then the readiness monitor shows "not ready", which can fail an inspection.