hi to all.... ok. I have a 1993 del sol si OBD1. I had code 41 (Heated o2 sensor heater, primary sensor) long time ago, I went to a honda used parts and bought Denso o2 sensor and install it. I also rest the ECU for more than 15 minutes and on the car, the ECU still throw me code 41. so I went back to the shop and they replace it for me and the code still 41. they change it AGAIN and still code 41 appearing (everytime i rest the ECU, but the ECU still throwing that code). the car is slow and my gas mileage is around 28 MPG (I think that's too much). so what should I do? the o2 sensor has 4 wires (2 black, 1 white and 1 green), I have tried to check the resistant on the 2 black and yes, i does have. but no resistant between the white and green. does this mean the o2 sensor is damaged or good? what should I do now?

 

Com'on guys? no body wants to help???

 

The failure of the original sensor may have blown the fuse. The two black wires are the heater circuit.

 

u need a new cat

 

What is the fuse no. for oxygen sensor? I searched around and I can't find something about o2 sensor fuse... anybody can help?

 

Why would a cat cause a primary O2 sensor fault, when it's upstream from the cat?

 

The heater element gets voltage on the Yel/Blk wire from the main relay and grounds on the Grn/Wht wire. Check the power wire for voltage and the Grn/Wht wire for an open.

 

Test ohms for a short between each wire and test each wire back to its source for an open, this is with the key off. Is that Denso sensor an OEM original or a alternate part number. Follow RonJ@HT above for the Heater Circuit test. Are you sure you have the correct connector plugged in, I know silly question, it happens, also, it has been known for folks to force fit connectors on backwards (usually on damaged connectors when you cant tell which way is which). What is the resistance of the heater in the HO2S also please.

 

Thank you Duane_in_Japan and RonJ@HT for your replies.

the connector fits perfectly, i don't think it has any problem. i just finish checking all the fusees on my car (under hood and under dash) and all of them are working. there is resistant between the 2 blk wires coming from the sensor itself but nothing between the grn and white (is that the normal thing?), im not sure how much is the resistance between the two blk wires (my device is analog, it reach the other end, the last. im not sure if my device read correctly). I also check for connectivity between the four wires coming from the plug(harness) which connect to my o2 sensor, every time i check two wires from the four for connectivity but all have nothing at all (I tried it while the switch is of and the other time while the car is on, still no connectivity). what should I do next? how can I know where is the problem?

 

BUMP!

 

Anybody???

 

https://honda-tech.com/forums/hybrid-engine-swaps-18/%5Bfaq%5D-%22my-vtec-doesnt-work%22-1812135/

halfway down is code 41 troubleshooting

 

Again, you need to do this: