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So my car had a check engine light that was for this transmission solenoid. I changed the solenoid but it did not fix the problem. So I found a electrical troubleshooting flowchart in the service manual and came to the conclusion that one of the 2 wires going to the solenoid was bad.(Shorted?) So I replaced the whole wire going from the solenoid to the computer with a new wire. I had no problems or check engine light for 2 months but now the same check engine light came back. What can be causing the wire to go bad?

Thanks  

is it the same check engine light  code????

if so.. which code..    oh.. and by the way.. what are you working on.. year.. make  model.. engine.. transmission..  really makes it easier than just taking a wild guess...

do you have a digital volt meter..  were you able to OHM the circuit..???   OHM the solenoid al the way from the disconnected harness at the  computer to the solenoid.

are there any switches involved in this circuit???    

did you use wiring with insulation that was transmission fluid proof???  

did you replace the transmission internal harness and connector plug where it passes through the case???

did you check the ground wires.. to the engine from the firewall  ... from the engine/transmission to the battery..  i have a two minute test i can post..     i have found on cars that liked to burn things up.. that when the engine was running and the headlights on..   that when i measured the voltage between the engine and the body.. there was 8.5 volts DC..  instead of 0.02 volts..    this caused all kinds of things that were grounded to the motor to act up and cook.  

if you have a digital volt meter.. try the test..

start the engine.. turn on the headlights...

set digital volt meter to 20 volt DC scale..

1. measure between the positive and the negative battery posts..    14.1 to 14.8 volts is expected..

2. measure between the Negative battery post and the engine block..  0.04 volts is expected..

3  measure between he Negative battery post and the body...     0.02 volts is expected..

4. measure between the body and the engine block..    0.02 volts is expected..

please post the results by number.. i will help you with them..

depending on the volt meter.. you might get 0.00 on the last 3 tests..   change the meter setting to 2 volts  DC and retest the last 3...  

This is a 2000 Honda Civic Ex. 1.6L.

Yes it's the same code as before. - P1753 - The transmission solenoid thing I replaced.

When I try driving it(step on the gas pedal),the car barely wants to move,(I have to floor it) then Check Engine Light Turns On and Off repeadetly and the D4 also flashes.

With the car on and lights off the volts between the battery terminals is 14.38.
When I turn on the lights I notice the instrument panel lighting dims down and the voltage at the battery is 14.20.

I have to go out and get a new multimeter because the one I got is crap.(no readings on tests 2-4 and no setting for 2 volts)  

they can be had for 7 bucks to 25 bucks..

a lot of parts stores have these from innova for about 16 bucks..



i actually like the harbor freight stores version   these are about 20 bucks



either will last you for decades..  

i take it that you have a service manual...

in the 2000 civic manual i have.. it shows 12 to 25 ohms for the lock up solenoid...

Measure Lock-up Control Solenoid
Valve A Resistance:
1. Turn the ignition switch OFF.
2, Measure the resistance between the b5 and A9 or A22 terminals.

is the resistance between 12 - 25 0hms?    


its on page 14-50 and 14-51 of my manual...


i don't do enough work on hondas to know more..  i do have a friend across the street who not only knows hondas inside and out.. but drag races them..  his honda civic is almost to 300 dyno measured horsepower.. without a turbo..   if you cannot find an answer.. i might be able to get in touch with him...

on the civic.. test 2 in the voltage drop.. is probably going to be close to zero do to the short short negative cable..    do the tests anyway.. its the first step that every electrical issue should be begin with..   i tested a chevy truck that had 8.5 volts on test 4.. engine to body..  man did it work better when i fixed that ground wire..  that truck kept burning out alternators..   please also .. as i don't like the drop when you turn the headlights on.  examine the battery cables under the rubber boots closely.. i have found a LOT with serious corrosion problems hidden..   if you have to clean them.. use HOT WATER.. and a stainless wire brush unless the corrosion is into the cable strands..  

Ok. Got my new multi-tester.

Test readings

1. 14.48V with lights off car running. 14.32V with car running and lights on.

2. Negative bat. to engine: -0.018

3. Negative bat. to body: -0.001 (I had a hard time getting a reading for this one. I even scraped a spot on the body with a wire brush so I could get a good contact.

4. Body to engine: -0.017  

those are all within spec..     so they are not a problem..


I had a hard time getting a reading for this one. I even scraped a spot on the body with a wire brush so I could get a good contact.    

usually one of the bolts that are attached to the firewall is good enough...    



 go on to test the resistance of the transmission solenoid ...

i am taking that you have a copy of the factory service manual to identify the pins..  in the ECM connector..  or access to that info...  

I check the resistance of the 2 wires going to the solenoid. The Yellow one which I replaced connects to D1. Resistance is 0.2.The second wire coming from the solenoid is Green with a black line, I think it connects to the D3 terminal on the PCM because I checked and the resistance is 0.2.

I did the flow chart again and now I got all the way to the bottom. It says check for loose terminal fit in the PCM connectors. Well Im looking for loose connectors but they all look fine. But I guess I should use my multimeter to make sure. So I stick one prong in the front of the D1 connector and one prong in the back of the D1 connector. 0.2 Ohm. D3: 0.2 Ohm. B20= 0.2 Ohm....
B22 connection terminal: -170 Ohm!

Now that I think we found the problem. Do I get a new harness or is there a easier way to change the B22 terminal pin inside of the connector?  

Found a video:
How to fix bad wiring harness terminal

Now I need to try to get one of those tools so I can pull the wire out.  

look in your manual.. it shows in some section how to depin the connector bodies...

there are at some parts stores like autozones... 2 depinning tools... both aluminum hex bodies with 6 various pins or tubes sticking out to unlatch the terminal fingers that are holding them in the plastic connector..
this is the green version..



and the red version..


i don't know if these will depin a honda connector..


sometimes this can be done with a sewing pin.. a paper clip...  i will try to find the section ...

 i normally use one of the carbide scribe tips to work the grip of the connectors tighter.. by closing them slightly...

more to come....


i paged though the over 1400 pages of the civic manual i have.. and it shows nothing on how to depin these...

usually there is a plastic keeper in the middle of the terminals that can be unlatched and removed.. then the plastic housing fingers can be slightly moved to free the terminals from the cavity...  

you will probably have to get individual terminals from honda..   or grab them from a junked car..  

Here is the harness connector. I am guessing the first step is to press the two tabs of the white part down and it will slide out...


 

ahh!!!!... 2  burned terminals in the upper picture..

looks like the white plastic device has to be Gently pried upwards as i bet there are legs that reach all the way down to latch all the terminals in place...

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there is a connector pin out chart in your manual.. please identify the 2 cavities with melting issues...

edit... looks like cavity 20 and 22....  but you already knew that...

identify the circuits and individually test them... for excessive resistance issues..  on the transmission end..  or if they are power circuits.. anything they operate.. yep..


i don't see any terminals inside that upper picture... did you pull the terminals out already.. or could it be possibly assembled wrong..   there might be small latches to lift to free the terminals..  

I didnt notice it before, but it does look like the terminal openings are melted in the picture.

The thing is I dont know where terminal 20 and 22 wires are going...Need to find that out.

I didnt pull the terminals out yet. I will be going to autozone to get the terminal remover tool.  

look at the page you posted above...  page 14-80....

its on the diagram on the right.. the EXACT circuit you are working with...    LG1 and LG2....

my manual says up to y2k.. but it really only covers up to 1999...  

This might be useful:
Honda Terminal Replacement Instructions