I have a d16y8 in my 1996 civic dx hatchback. I was having a problem with the speedo being erratic and I ruled out fuse 15 and basically everything. The last thing I needed to do was replace the alternator which I did. After I replaced the alternator the battery light was on and I went to get the battery checked and it was bad so I replaced the battery. Battery light is still on... and the VSS CEL was coming on after that. (the VSS is new as well) So I decided "screw it" I'll just replace the wiring harness because the wiring was super janky anyways from the previous owner. I bought a MT EX d16y8 wiring harness... I didn't know that I would have to wire the 2nd o2 sensor... but that's another story. I swapped the harness and now I'm getting 3 CEL's AND THE BATTERY LIGHT IS STILL ON! I knew I would get the CEL for the bank 2 O2 sensor because it's not wired yet. A lot of coolant leaked out of my car while doing the swap because I had to remove the Intake manifold so that explains my Idle air control valve p1508. And I'm getting CEL for bank 1 o2 sensor which is also confusing me. I'll replace the sensor because the wiring was cut on it and it's probably messed up. but WHY IS MY BATTERY LIGHT ON! AFTER ALL THIS **** LOL.

Thanks HT

 

Reset the ECU.

Run engine until CEL remains on steady.

Pull the codes.

Post the actual codes.

-----------------------------------

Is the alternator belt tight and are all alternator mount bolts tight?

 

Clean the battery terminals and ground wires. Battery brushes are cheap at the auto parts store. Get one.

 

The wires for the light and speedo could be shorting out on the intake bracket and causing problems. Only the hot wire shorting will actually blow fuse 15. Everyone with a '96 needs to get under the car to check the harness and repair if necessary.

Also the new alternator could be defective. The battery light is driven only by the alternator. If you unplug the 4 wire plug from the back of the alternator and turn key on, light should NOT light.

 

yes but I'll double check

the car won't run long enough because of the IACV problem I'm having. The idle is way too low. I'm going to be working on it tomorrow and I'll post up some answers

 

Codes I'm getting are P1508, P0135 and P0141... I just put in a new o2 sensor on the exhaust manifold and I'm still getting a code for it. As i said before, I don't have the 2nd o2 sensor wired yet... and the first code is for IACV circuit. My coolant was low so I added coolant and reset the codes and it still came up. I unplugged the IACV as well and still didn't run fine.

I'm going to check the belt and the mounts right now on the alternator.

 

What year harness did you get as a replacement. You need the 96-97 obd2a harness in your 96

 

I bought a d16y8 obd2a harness from ebay it says "1996 1997 1998" I think the IACV plug is a 3 plug on it... there is a green black wire 2 connector plug... and a 3 connector plug with blue/blk orange and another color. I thought that the harness I got I would not have to rewire the IACV but maybe I was wrong? I'll have an open green black plug which I think is for if i had a air temperature sensor on my intake manifold but I don't.

 

Also, all the write ups I've seen on the IACV 3 port to 2 port conversion say that I have to repin the blu/blk wire in the ecu and remove the orange wire. The ecu plug already has the blu/blk wire in the CORRECT spot and the orange wire is already gone...

 

The first picture is the IACV plug (I think)
The 2nd picture is a plug that will be left open if I'm correct about the IACV plug being the first picture. That's what I was using at first and obviously it wasn't working.

 

Is your car manual or automatic, and is the harness you bought for a manual or automatic. They do have different plugs

 

As far as the speedo goes; if you've replaced the vss and the harness, the only thing left to shotgun is the cluster itself. These cars have a history of the worst speedo reliability... best of luck

 

My car is manual and the harness said it was from a manual transmission civic.

 

You have a 3-wire IACV connector but you need a 2-wire connector and IACV.

Do this^ test suggested by mk.

For P0135, Ohm test the primary O2 sensor heater element and check whether it receives battery voltage from fuse 15.

 

OK I will post results.

Ohm test the connector on the harness side for the heater sensor element wire to body ground? I have a multimeter but new to using it. Lol

 

Heater element side - Measure resistance (Ohms) between the two heater element terminals (black wires). The reading should be 10-40 Ohms.

 

Thank you. Give me a bit and I will post results of everything

 

Tested the resistance of the new primary o2 sensor I bought and its 8.4 Ohms (the wires were white on the bosch o2 sensor i bought). I looked up some troubleshooting for the o2 sensor code I'm getting and did some volt tests that it was suggesting... It doesn't look like I'm getting any voltage going to the connector on the harness side it was telling me to test. That means that the heater element isn't getting any power for some reason. I did the test with the KEY ON position obviously... I did not have my ECU connected though... if that can cause a problem let me know and I will retest

I checked fuse 15 for continuity and the fuse is still good.

I did the test with disconnecting the alternator plug and the battery light turned off.

 

With key in ON(II), the Blk/Yel wire (wire harness side) should have battery voltage to body ground. If it doesn't, do the same test on the Blk/Wht wire in the secondary O2 sensor connector.

Replace the alternator.

 

I don't have a secondary o2 sensor connector as of yet, I was going to wire it after I got everything else working. I did that test with my multimeter grounded to the negative battery terminal to the blk/wht wire (harness side) had 0 voltage and I just tested the blk/ylw wire and I got 0.5 volts only.

 

while I was testing fuse 15 for continuity I saw this plug dangling in the back of the fuse box. Is this plug important? I couldn't seem to find anywhere it would go.

 

What are the two wire colors running to the spliced connector?

Test for battery voltage at the Blk/Yel wire in C101 and the Blk/Wht wire in C432.

 

blu/wht and blk/wht for the spliced connector

 

0.54 v with key on at blk/yel wire on c101. Let me get to the other connector you are asking about

 

If you meant the small blk/yel wire in pin "1" it was 0.54v and if you meant the one for pin 10, the big ignition one I got nothing.