fred44

Hi,

I’m having a puzzling issue with our 1999 1.4 Civic and really hope somebody can help.

The engine light came on and the fault code was 41.

I reset it and it didn’t come back but the engine just didn’t feel right, especially at tickover.

41 shows the 02 sensor so I just replaced this with a new BOSCH one (so not Honda but should be a good brand).

Since doing that the engine still runs not right (really low tickover, sometimes stalls) but the engine light is just on all the time. Even after a reset it just comes back after about 5 seconds.

I have checked fuse 15 with a multi-meter and that is fine.

I have tried to follow the TSB to do with the wire wearing through, but everyting looks fine.

The sensor has 4 wires…. two white, a grey and a black.

This probably doesn’t help but I tested resistance on the two whites and got 6 ohms.

Can some kind person please help me out and tell me what things I should be
testing?

Thanks in advance

Fred

Former User

Does the power wire for the O2 sensor heater element get battery voltage with the key in ON(II)?

fred44

Thanks for getting back to me on this, much appretiated :-)

Sorry for my stupidity...

Do you mean the black and grey wires?

Or is one positive and the negative is just ground from the car?

EDIT...

I have just figured out white & white is the heater, grey is earth and black is signal.

I will pop the multimeter on white white (or balck balck as it is on the Honda side) and see what I get.

fred44

Tested and its 12.6v

I guess thats a good start?

Former User

Was the Bosch sensor plug & play or did you need to splice wires?

fred44

Plug and play.

The two white wires are to the bottom, the same as the one that came off.

I thought the one I took off was the original (It says NTK, but no Honda badge) and was expecting different colours (black instead of white) but they are identical to this new one.

anthony_kim

bump

fred44

I have no idea how you would test that.

I'm confident its sensor reated though because the light went from being now and then to all the time with this new one.

fred44

Are there anymore tests I can do?

Former User

If the wires and sensor are good, try swapping in a known good ECU.

fred44

Does it have to be from an identical 1.4 or are they all pretty much the same? (this is the 98 bhp version).