1999 Honda Accord Code P0740 Torque Conveter Clutch Solenoi

LOVEHONDA

MEMBER
1999 HONDA ACCORD
6 CYL
FWD
AUTOMATIC
170,000 MILES

Hi!

I have question related to the transmission. The car start slip gear when I shift to D4 or 1, 2 or D3, the RPM jump to 2000 but the car doesn't move much. The CEL on and I pulled out the code P0740. I right away changed the transmission fluid, unussually in the old transmission has a lot of metal deris. I also troublshoot and clean Lockup Control Solenoid Valve Shift Control Solenoid Valve A and A/T cluth Pressure Control solenoid Valve A/B. All of two unit above pass the Ohm test within the range and click sound heard when test. Also no futher code fail for the 2nd, 3rd clutch pressure switch. The car run fine after I changed Transmission fluid but the unfortunatelly, the CEL still on with code P0740. The RPM also some time jump little on low speed 10 or 20 MPH or when I stop on the red light or Stop. Please let me know what wrong cause for the code P0740? Is the Torque converter failed or the whole transmission dead? The car run fine but still had error code P0740 and RPM will jump when slow speed.

3 Replies

KHLOW2008

MECHANIC
41,815 POSTS

Hi lovehonda,

Here are the diagnostic procedures for the trouble code.

DTC P0740/40: LOCK - UP CONTROL SYSTEM

NOTE: DO NOT perform this DTC test until all other DTCs have been repaired first.

1. Using scan tool, retrieve A/T freeze data. Clear fault codes and road test vehicle under same conditions freeze data was recorded. If fault code returns, go to next step. If fault code does not return, problem is intermittent, check transaxle and PCM connections.
2. Using scan tool, check for any other DTCs. If any other DTCs are present, repair those DTCs first, then recheck for DTC P0740/40. If no other DTCs are present, go to next step.

3. 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.

4. 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.

5. Replace lock-up control solenoid valve/shift control solenoid valve "A" assembly. Turn ignition off and clear codes. Road test vehicle at over 50 MPH for more than one minute. Recheck DTCs. If P0740/40 returns, go to next step. If P0740/40 does not return, system is okay.

6. Replace A/T clutch pressure control solenoid assembly. Turn ignition off and clear codes. Road test vehicle at over 50 MPH for more than one minute. Recheck DTCs. If P0740/40 returns, go to next step. If P0740/40 does not return, system is okay.

7. Replace torque converter. Turn ignition off and clear codes. Road test vehicle at over 55 MPH for more than one minute. Recheck DTCs. If P0740/40 returns, replace transaxle and torque converter. If P0740/40 does not return, system is okay.