Wytas

I got a 98 Honda Civic DX that is throwing codes P1298, P0420, P0700, P0740.
P1298 - If i replace the ELD i believe this will fix it?
P0420 - Cat Converter - Was told to pour lacquer thinner in gas tank to try and clean it or manual try and clean it before replacing it
P0700 - A/T system malfunction - this would be the shift solenoid?
P0740 - TC clutch system failure - this would be the torque converter solenoid?
Is there a difference in the shift and torque converter solenoid? I've replaced the shift solenoid years ago. Could the one code be the cause of another in this instance? The car starts, runs and shifts fine.

mk378

When you have multiple codes but car seems to work OK, make note of them then clear them all and drive until the CEL comes on again. Then see which code reappeared, and concentrate on that one.

ELD codes are often spurious.

Wytas

I did, the first time i had it scanned it had 5 codes (the 4 listed + P0302) then i unplugged the back up radio fuse under the hood, drove it 200-300 miles and the C.E.L came back on throwing the 4 codes listed above.

civic402lx

When the p0700 present, was the D blinking green?
check your connection on the o2 sensors. Make sure they are plugged in tight and secured.

tony_2018

Check engine harness under the intake manifold to see if its damaged

Wytas

The "D" light was never blinking, i will check the harness and make sure the sensors are secured.