P0740 code

PMP

MEMBER
1998 HONDA CIVIC
4 CYL
4WD
AUTOMATIC
136,000 MILES

I have the check engine light. P0740 tcc circuit malfunction. What can I check to fix this I tried everything I can think of? Nothing is wrong with the transmission it shifts with no problem and the fluid is full and fresh genuine Honda tranny fluid. I reset ecu and PCM by removing thE fuse for it and it went off then I went 55mph and stayed for few minuutes and it came on it's done this a few times all at 55mph. Please help. Thank you

1 Reply

KHLOW2008

MECHANIC
41,815 POSTS

The TCC does not affect shifting. It only affects the lockup system and would normally occur at constant driving speed.

DTC P0740/40: LOCK-UP CONTROL SYSTEM
NOTE:
DO NOT perform this test procedure until all other DTC have been
repaired first.

1. Using scan tool, check for any other DTC. If any other DTC are present, repair those DTC first, then recheck for DTC P0740. If no other DTC are present, go to next step.

2. Test line pressure. If line pressure is within specification, go to
next step. If line pressure is not within specification, repair hydraulic system as necessary.

3. Test clutch pressure. If clutch pressure is within specification, go to next step. If clutch pressure is not within specification, repair hydraulic system as necessary.

4. Replace lock-up control solenoid valve assembly. Turn ignition off and clear codes. Ensure engine coolant temperature is 176°F (80°C) or greater. Road test vehicle at over 55 MPH for more than one minute. Recheck DTC. If DTC P0740 returns, go to next step. If DTC P0740 does not return, system is okay.

5. Replace torque converter. Turn ignition off and clear codes. Road test vehicle at over 55 MPH for more than one minute. Recheck DTC. If
DTC P0740 returns, replace transaxle. If DTC P0740 does not return, system is okay.