Loyalhondahaver

Hello all. Just swapped a y7 from a 99 Civic LX into a 00 Civic EX.

I used the y7 harness and computer.

5-10 seconds after start up, I get code 65. I swapped computers with another and also get code 65.


Ron J posted this info on another "code 65" thread years ago:



The O2 sensor wires (ignore these wires for code 65):
1. Wht to Wht/Red wire pins to ECU D14.
2. LtGrn to Red/Yel wire pins to ECU D13.

The heater element wires:
3. Blk to Blk/Yel wire that gets power through dash fuse 15 should have battery voltage with the key in ON(II).
4. Blk to Blk/Wht wire pins to ECU A5.

The following three tests are done with all ECU connectors plugged in and the secondary O2 sensor unplugged:
a) Is fuse 15 blown?
b) With key in ON(II), do you measure battery voltage between terminal 3 (+) and terminal 4 (-) in the O2 sensor wire harness connector?
c) With key in ON(II), do you measure battery voltage between terminal 3 (+) and engine ground (thermostat housing) in the O2 sensor wire harness connector?





I did these tests, (kind of).

I didn't use a multimeter but a test light.

My test light lit up for both test B and C.
Fuse 15 is not blown.


Should I use a multimeter now (must get one and learn to use it) or will my test light test suffice?

I have swapped the secondary o2 for two other known good ones and the code reappears in the same amount of time. (ECU reset every time before testing)

Help!

Former User

There could be a short in one of the heater element wires or the Y7 ECU is bad.

Start by buying or borrowing a multimeter.

Also post a picture showing the wire harness connector for the secondary O2 sensor and the 4 wire colors.

Loyalhondahaver

Step one- complete. Headed home for testing. Have to figure out where to set the dial.

Former User

Multimeter Tutorial - Voltage

You will use the Ohms (resistance) and DC voltage settings. I didn't see a continuity setting on your multimeter, but that's not required.

Loyalhondahaver

Thank you. I'll probably have to return this one later and get one that can test for continuity for when I master the thing. Studying now!

Former User

The Ohm setting is sufficient to test for continuity.

The only difference is that the continuity setting makes a beep sound when continuity is detected. It's really just a convenience feature rather than a required feature.

Loyalhondahaver

My secondary o2 plug and it's wire colors.

Former User

Good. That's the correct plug.

Start by measuring voltage across your two battery posts. Install meter probes. Dial the meter to the 20V DC range. Touch red meter probe to (+) post and black meter probe to (-) post. The reading is referred to as battery voltage for your car.

Loyalhondahaver

Test c:
on the harness side connector for the secondary o2, (the one pictures) the black/yellow wire to body ground give me 11.92 v. With my multimeter set at DCV 20.

Test B:
On the harness side connector for the secondary o2, (the one pictured) the black/yellow wire to the black/white wire i get no readings.

Bad black/white wire?

Former User

These^ two tests are the same as B and C using a test light in your first post. Why are you now getting different results using the multimeter?

Loyalhondahaver

I guess I messed up some how. Possible I did the test with other other ECU. Although I got the same code with both ECUs, I'll switch them again and see if I get the same results.

Former User

Turn key to ON(II) and then repeat test B.

Loyalhondahaver

Key turned to ON(II), repeated test B with both ECUs, same results- no reading.

Loyalhondahaver

I did that. No readings. Also just threw in a y8 ecu and tested, no reading.

Former User

Can you locate this connector?

Loyalhondahaver

Yes, I have located it.

Former User

On the male-pin and female-pin sides of C131, are there Blk/Wht wires at pin 1?

After you have the answer, look at these two diagrams:

D16Y7


D16Y8

Loyalhondahaver

There is a black/white on the male side and nothing on the other side.



Studying now.

Former User

The missing Blk/Wht wire is the problem. The 99 Civic LX D16Y7 harness had a Blk/Wht wire on both sides of C131 (pin 1), but the 00 Civic EX did not because the Blk/Wht wire bypassed C131 and went directly from C432 to ECU connector A.

Loyalhondahaver

Awesome! So I believe I have two options:

1. Install 99 LX cabin harness

2. Depinned the black/white wire we are speaking of and pin in into the correct spot on connector A.

Does that sound right? Option 2 sounds like the best idea.

Former User

The missing wire is on the engine harness side of C131.

Loyalhondahaver

Thanks so much Ron.

Working on depinning now.

I have the existing black/white white from the y8 cabin harness depinned. (Commector A slot 8)

Now I'm working on depinning the black/white wire from the male side of connector 131 from the y7 harness. This connector pins differently it seems. Not as easy to depin.

Then I will pin black/white wire from c131 into slot 8 or connector A, leave old black/white hanging and she should work!

What website do your factory diagrams and what not come from?

Former User

Are you using the Y8 secondary O2 sensor that plugs into the cat under the console or the Y7 secondary O2 sensor that plugs into the header/cat combo at the front of the engine?

Locate the 96-00 Civic service manual in a Google search and download it.

Loyalhondahaver

I am using the y7 sensor that plugs into the bottom on the cat on the bottom of the exhaust manifold.

Former User

1) Test the Blk/Wht wire on the male-pin side of C131 for continuity with pin A8 in ECU connector A. If you find continuity, proceed to step 2.

2) Run a new Blk/Wht wire from the secondary O2 sensor connector to the female-pin side of C131.

There should be no code 65 after this is done.