Hi, I have a 2000 accord 2.3 ULEV and I just replaced the front o2 sensor (no CEL just getting very slow) I replaced it with a 4-wire universal standard auto parts sensor and now i get a heater system malfunction code only on cold start. Now, if i clear the code after it comes on it won't return until the next cold start but if i turn the key on for about 10 seconds before I start the car, it's fine. so it seems like the sensor is just slow warming up and causing the code, I checked the o2 sensor heater with an ohm meter and it's fine. Also, the light comes on about 20 or 30 seconds after startup everytime. It has the stock exhaust and no mods. any ideas?

 

What specific trouble code are you getting? If the car is an ULEV, it needs an Air/Fuel Ratio sensor. Was that what was installed?

Also, sometimes if the wiring connections are loose using crimp type butt connectors on a universal sensor that may be causing the heater malfunction code.

 

the code is p1167- sensor 1 heater system malfunction. Not quite sure what you mean about an air fuel ratio sensor, that's what an o2 sensor is. I'm gonna check the wiring, because i did have a little trouble with the pins in the connecter, so i'm gonna make sure they are in there snug.
thanks for the fast reply

 

OK, I stand corrected, there is a slight difference between an oxygen and air fuel ratio senor, specifically the latter HEATS UP FASTER! so I'm going to go get it exchanged for the right one, since i said it was ULEV and they gave me the normal one.

 

Generally, an air/fuel ratio is a wide-band oxygen sensor, while many of the regular oxygen sensors are narrow band. Also, if your car is an ULEV, the ECU will keep setting the code until a proper air/fuel ratio sensor is installed.

 

Make sure the parts store lists a different sensor for the 2000 ULEV engine vs. the 2000 non-ULEV engine. If their parts list calls for the same part, say thanks & goodbye because they ARE different.

 

OK I found out that the problem is they sold me the downstream ULEV sensor which is the same as the upstream non-ULEV sensor. so it was they're fault but they tried to tell me that they couldn't take it back because it was already installed!! but I talked to someone different later and they refunded my money and a new direct fit OEM sensor will be here tomorrow. Thanks for the help, i probably would have still been searching for a wiring problem had i not known there were 2 different sensors.