P0740 code showing in my 2000 Honda Odyssey

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.

see a relative link
http://www.hondacarforum.com/honda-3/22348-2000-honda-civic-radio-error-code-problem.html

P0740 is torque convertor circuit malfunction,To access the solenoid you need to remove the air intake boot, The TCC is mounted at the top of the transmission, Remember you are dealing with a circuit malfunction this can be a bad wire connection or,a bad solenoid,

You can get a reman trans for about $2500 or rebuild yours
for $1700 locally

The misfire could be spark plugs & a couple of ignition coils
you do for $100

Egr about $80 you do

You need the trans diagnosed at a trans shop & road tested

that is your pressure control shift solenoid

Hi there:
DTC P1361 - TDC sensor intermittent interruption



Here is the actual bulletin : HONDA TSB LINK


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is a car

P0740 - Torque converter clutch solenoid circuit

Could replace solenoid if no other damage to transmission, sit under transmission remove pan and valve body unbolt slide right out, to get part need to all a transmission parts place, reguler auto parts won't have it.

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

Code p0740 is a problem in lock up control solenoid assembly, Check whether scan tool indicates another code. Does the scan tool indicate another code? YES - Perform the Troubleshooting Flowchart for the indicated Code(s). Do not continue with this troubleshooting until the causes of any other DTCs have been corrected. Measure the line pressure. Is the line pressure within the service limit? Repair the hydraulic system as necessary. Replace the Lock-up Control Solenoid Assembly set lock-up control solenoid valve/shift control solenoid valve A assembly and the A/T clutch pressure control solenoid valve A/B assembly. Turn the ignition switch OFF, and reset the PCM memory by removing the BACK UP fuse in the passenger's under-dash fuse/relay box for more than 10 seconds . Using the scan tool, check to be sure that the engine coolant temperature is 176°F (80°C) or above . Drive the vehicle at 55 mph (88 km/h) for more than one minute . Recheck for code P0740. Does the OBD II scan tool indicate code P0740? YES - Remove the torque converter and inspect for a missing torque converter O-ring. If the O-ring is damaged or missing, replace the transmission and torque converter. NO - The system is OK at this time.