P0740 code meaning
Torque Converter Clutch Circuit/Open
Powertrain system Generic code P07xx codes Check engine light
What P0740 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. P0740 concerns the control circuit of the converter clutch solenoid. Ford flags an open circuit when the driver feedback line disagrees with the command for 0.5–5 s, with MIL; a 2006 GM table checks 0/12 V with more than 43 of 50 failed counts after two trips – newer GM units use P2761/P2763/P2764. FCA's Ram 6.7 reads P0740 as converter slip out of range and moved it to two trips by software in 2013. The clutch is then switched off: higher engine speed when cruising, more fuel, hotter fluid.
P0740 at a glance
- Check engine lightYes, usually on
- Emissions testCan fail
- Limp modeNot expected
- Repair difficultyMedium
- Typical labor1 to 4 hours
- Clears after repairAfter a drive cycle
Symptoms of P0740
- Check engine light or transmission warning
- No lock-up: engine speed about 100–300 rpm higher when cruising
- Higher fuel consumption, hotter transmission fluid
Common causes of P0740
- Most likelyOpen or corroded harness or transmission pass-through connector
- PossibleConverter clutch solenoid coil open
- PossibleInternal transmission harness or mechatronic unit
- Less likelyDriver stage in the module faulty
- Less likelyFCA: actual converter slip (clutch wear, fluid) or software
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 P0740 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. |
| 40 | The exact fault in that area. |
What to do next
- Note P0740 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 P0740
What does P0740 mean?
P0740 means "Torque Converter Clutch Circuit/Open". 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 P0740?
Usually yes, for a short time, if the check engine light is steady and the car drives normally. If the light flashes or the car runs badly, stop and have it checked.
Will P0740 fail an emissions test?
Yes, it can. P0740 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 P0740 to fix?
Difficulty: medium. A typical repair takes 1 to 4 hours of work. This is a job for a workshop.
Will P0740 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.