Rep Power: 0

Hello all,

I have an '04 Civic DX. Engine light is on and if I start the car to warm it up (cold up here in Canada), it stinks like exhaust inside the car when I get in. Smell goes away when driving or when car is good and warm, but here's another issue that may tie in. The car does not heat up much (meaning, air from the heater vents) when idling in cool/cold weather. Once I start driving there's plenty of heat pumping out though. The thermostat says the temp is fine however. And the car runs fine in most respects. No loss of power, stalling, etc.

I took the car for an E-test, it passed but the shop said that the diagnostics said O2 sensor 1 was giving an error. I told them to leave it be for now.

So before I go replacing the O2 sensor, would any of these problems be caused BY the O2 sensor malfunction, or is the sensor detecting another problem?

 
Rep Power: 234

Get the code read and post the exact code.

Even without the code I can tell it's probably the sensor(s) are bad or a bad catalytic converter.

 
Rep Power: 0

The code is:

P0135 O2
Sensor 1 heater circuit malfunction

I did some searching, it seems either the sensor itself is bad or a fuse/wire problem?

 
Rep Power: 313

Your exhaust smell is probably an exhaust leak. Mine smells like that too and the exhaust leak is located right after the catalytic converter at the joint.