Check engine reads P0740 honda civic ex 2001... do i need to replace the transmission control solenoid?

P0740 is the torque converter malfunction code. The converter is in between the engine and transmission. The fluid that you are seeing is transmission fluid. It needs to go to a mechanic to narrow it down from there.

This code is set when the transmission control module detects improper voltage at the torque converter clutch. This can be caused by low tranny fluid/dirty tranny fluid/defective torque converter clutch solenoid/electrical connections to from solenoid

On some cars, there is a TCC solenoid in the transmission which can be replaced by removing the bottom pan. In some cars this solenoid can't be accessed without major disassembly.

P0740 Honda - Transmission Lock-Up Control System Fault Possible causes
- Low transmission fluid level
- Dirty transmission fluid
- Faulty torque converter clutch solenoid valve
- Torque converter clutch solenoid valve harness is open or shorted
- Torque converter clutch solenoid valve circuit poor electrical connection

Tech notes
On some Honda vehicles the P0740 code may be set by an overheating torque converter problem which is caused by an insufficient flow to the torque converter release circuit.

P0740 Honda Description
The torque converter clutch 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.
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.

its the transmission linear solenoids not the torque converter solenoids. you can buy the linear solenoids on ebay for about $100

DTC P0740 - Torque Converter Clutch Circuit Malfunction





It sounds like you need new solenoids in valve body you have a open circuit in the T/C clutch solenoid valve in valve body, I would replace the solenoids to fix your problem and inspect all connection to transmission valve body.

The valve body will need to be removed to get the valves replaced This can be a little hard if you have not done this before it comes with harness and solenoid pack together.

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P0740 Trany converter clutch system failure
Since this is also a trany problem, test this code by getting a complete wiring diagram of the trany electronic circuit. Once you have it and identified the location and colors of the torque converter solenoids/module, it is a matter of measuring the resistance of the TCC solenoid and comparing it to all solenoids. If defective, it is will either show open or shorted connection. Don't forget the basics like checking the wires for integrity of insulation and routing (making sure the wires are not rubbing a metal or being burnt by the exhaust). If there is a chance that the solenoid needs to be replaced, drop the trany oil pan so you can verify for signs of debris.
TIP:
To manually test your TCC solenoid before replacing it, you can feed direct battery voltage on the supply side of the solenoid and you should hear it click. Also try to test the connections between the TCC module and the engine module.

get your torque converter and torque solenoid checked out or replaced my civic had the same issue and that fixed the problem

unfortunately it is. Contact your local dealership to see if it may still be covered under a warranty or not.

Customer Concern: The check engine light is on with the trouble code P0740 present. Tests/Procedures: 1. Test drive the vehicle and watch the tachometer. See if the automatic transmission locks up. If unable to see the RPM change, and the Engine Control Module (ECM) is turning on the lockup solenoids, then the problem has to be internal to the transmission. The transmission has an extended warranty from Honda for 7 years or 100,000 miles. Potential Causes: Automatic Transmission
Lock-Up Solenoid
Torque Converter
Tech Tips: TSB #02-062 Diagnostic Codes: P0740

Horsecrap...go to an independent transmission dealer after you call the extended warranty folks and complain!
I can count the number of Honda transmissions that go bad before 300,000 miles on one hand.
Good Luck