[Rivianer]

Looking for anyone knowledgeable on D17a2 wiring harness or just know how with electrical on 7th gens.
I have a 2002 LX ECU and harness on a swapped D17a2 and am dealing with what I suspect is a wiring short somewhere.
I'm getting CEL for high voltage on upstream O2 sensor consistently and every once in a while knock sensor malfunction. Then sometimes CEL goes away after start up and stays gone driving around town and even after engine stops and starts, but comes back on if I go over 65mph. Yeah, weird. It's a new O2 sensor on upstream only. Any help appreciated! Thank you.

 

[drtalon123]

How knowledgeable are you with a multimeter?

Grab some schematics, a multimeter, a test light and baseline the circuit from ECU to sensor.

What brand sensor did you use? Is this a California emissions spec car? How many wires does the upstream sensor have? 4? Or more?

 

[Rivianer]

I've used a multimeter to test outlets in house but that's it. I'm willing to learn but I dont want to fry anything. I'm not sure the brand sensor, a friend gave it to me saying it's new and it looks new so theres a chance It's bad from the get go. It has 4 wires. And nah, it's Georgia so emissions dont matter. Lol
I'm going to purchase a multimeter and test to see if it's just a bad sensor.

 

[drtalon123]

I've had newer honda OBD2 ECUs complain when Bosch typical 4 wire zirconia sensors are used for some reason. There is something about the OE brand sensor (NTK) they seem to prefer over Bosch.

Install an NTK and it no longer complains. I'm not saying this is what is wrong in your situation, just an observation from the numerous times I've had customers come in saying:

Customer: "checked my engine light at an auto zone, cleared the code and it came back. Rechecked code at same auto zone, said it was throwing for an O2 sensor. I bought one and put it on myself. Cleared codes at the same auto zone, but the light still comes on."

Me: (Checks codes, has fault for sensor heater open/shorted or sensor voltage high. Look and clearly see its a Bosch sensor.) Sir, do you know what brand sensor you installed?

Customer: No, but I have the box! (Hands me a Bosch O2 sensor box).

Me: When did you buy this?

Customer: Yesterday.

Me: I'm going to take it off the car, and I want you to try and return it to auto zone and get your money back.

Customer: Why? How come?

Me: Because this is what's causing your check engine light. You'll need a different brand sensor from NTK, which is the OE brand. The ECUs are known to complain with Bosch sensors. Unfortunately it is almost twice as expensive.

Customer: Really?

Me: Really.

Customer: OK, go ahead

Me: (Gets sensor, installs, clears codes, takes for short test drive, couple key cycles, no codes. Gives car back to customer. Customer never returns.)

 

[Rivianer]

Well alrighty then. Lol Thank you! I'll check to see if it's a Bosch. I'll do the multimeter test soon and look into getting a NTK. I'm hoping this is the case and not a bigger fault with the wiring harness. I'll post my results. Again, thank you!

 

[Rivianer]

So the sensor the sensor that was in there turned out to be from YLCN brand. The guy I payed to do it for me when I was working during the holidays got the cheapest chinese crap off Amazon. I just installed a NTK sensor, drove around for a while and no CEL yet. Hell yeah.
Thanks for the advice!

 

[drtalon123]

YLCN, is that an acronym for "You're Lucky you're Crap is Not too fucked"?

I've never heard of that brand haha

 

[Rivianer]

Hah! For real. Lol Yeah, some second rate wannabe brand. After more driving this evening the CEL still hasn't come on. Whereas during the same driving the code would've tripped again with that crap sensor after disconnecting the battery. So all's well!
(For now) lol Keeping my Civic forever alongside the farm truck. Only at 183k now and aiming for a 400k life, or more! With yalls help it just might be possible. Haha