Execut1ve

Hello all,

I just did some pretty involved work on my civic (2000 EX d16y8). Replaced clutch, rear main seal, oil pan gasket, oil pump, and water pump gasket. To do all this I had to drop the exhaust. I disconnected it immediately after the manifold and also immediately prior to the muffler next to the right rear tire. For a moment during the process the weight of the exhaust was hanging from the wiring of the rear O2 sensor. As a result the spades came out the back of the wiring connector when it came loose. I was able to reinsert the spades into the back of the connector and it seemed to go back together fine.

Now everything is back together, seems to be running smooth with the exception of a CEL, which is being caused by codes 135 and 155 (both O2 sensors). Anyone else had this happen following dropping a significant portion of the exhaust?

Also, does anyone have any tricks for getting the alternator belt tension right? stupid thing is in a terribly awkward spot, I can't seem to push it out enough to get that last little bit

Thanks!

ezone

First guess is sensor damage due to yanking the wires.
Second guess would be that you didn't get the wires back in the correct holes in the connector.
Third guess, collateral damage from either of the above: blown fuse for the heater circuits, roasted PCM, etc.
A good service manual can be of great help to you.
Prybar.
Or maybe your belt needs to be a tad bit shorter.

xRiCeBoYx

iTrader: (22)

I'm gonna hop on the sensor damage bandwagon. Every time I have to take my downpipe off, I disconnect the O2 sensors first.

Execut1ve

good thoughts from everyone so far. Just got back from a trip from OH to NC and back and got excellent fuel econ (~40 mpg) so the primary O2 sensor must be functioning.

I do have a service manual, after some reading I determined that the rear O2 sensor (the one in question) is the secondary sensor and only exists to verify the proper function of the primary O2 sensor and the cat

I checked the colors of the wires when I reinserted them into the connector, using the harness side of the other connector as reference. all the colors matched up, so I just put the wires in the corresponding holes

I have looked over the fuses and checked all the 7.5A ones in search of fuse 15, have not yet encountered any blown fuses. doubt very much that the computer is damaged if I can drive ~900 mi with such excellent fuel economy

I'm reasonably confident in the belt, as it's the same one that was on beforehand and I didn't previously have any belt squeal problems. tomorrow evening I"ll go at it with the crowbar

Tomorrow I will also verify that there is voltage across the 2 heater wires when the key is turned

Thanks all for the advice so far!

ezone

Sensor wire positions in its connector half do not always match the vehicle harness pin positions when only looking at the colors of the wires.


There's more, but that's close enough for government work.

Check both fuse boxes. Check all the fuses.

A wiring diagram shows: The O2 sensors share the 7.5A ALTERNATOR/SP SENSOR fuse #15 in the dash fusebox.
If it is charging, then the fuse is probably good.
You'd be surprised, and it depends on the design and if there were any built in safety protections used by the design engineers.
A PCM (or any computer, etc.) can have a single circuit or output drive transistor wiped out, literally blown off the board-- and yet all the rest of its functions can still work normally.

It's not like it got hit by lightning and melted everything inside the box or something.

I just tossed it out as a possibility, because it IS a possibility.

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

Wires:
Sensor side | vehicle side

1) White | White/Red
2) Lt. Grn | Grn/Blk
3) Blk | Blk/Yel
4) Blk | Blk/Wht


3 of the wires should be in the same positions as the wire positions on the front sensor. G/B, B/Y and B/W should be in the same spots of the vehicle harness connector.

The blacks on the sensor are for the heater. Really they are interchangeable.
The other 2 are for the sensor element.


HTH

Execut1ve

small status update... I found a diagram that labels which fuse is #15 and checked it, was not blown.

been hunting down another electrical problem lately so haven't had time to concentrate on this, also it's been rainy and nasty here lately

I did get my alternator belt squeal worked out though, used a crowbar to get sufficient tension on the belt

thanks for the wire color information, I will look at the connectors again and verify that it is wired correctly