Remove Cat installed Test pipe - CEL on, as expected

[Blainethemono]

I did this a while ago on my 89 Prelude. Removed Cat convertor, installed test pipe. Check engine light came on after about 5 miles later, came on every time the engine warmed up. I disconnected the battery to drain the ECU, did my due wait, reconnected & it hasnt returned since.

Same scenario with the Accord, but the CEL comes on even after pulling power to the ECU. Engine runs just fine no issues, but Im wondering if Im going to have to hook a O2 sensor to the Test pipe & wire it in to resolve the light issue.

Question do I just splice it into 1 of the sensors on the exhaust? If so does it matter which one?

Thanks

[Oldblueaccord]

I would check the code.

There is no 2nd O2 sensor after the cat on these cars.

[Blainethemono]

Yeah, I didnt think so

Code 12 Exhaust Gas Recirculation System??

Wooo Boy! Read several threads in the EGR valve...... Car runs just fine. Idles fine, gas mileage it fine, just the CEL light is on all the time


Ill check the EGR valve, this may be just a coincidence, but my Prelude did the exact same thing when I went test pipe, & disconnecting the battery for 20 seconds & resetting the ECU cured it & it hasnt come back. The Accord is being more persistent.

[Oldblueaccord]

Yeah, I didnt think so

Code 12 Exhaust Gas Recirculation System??

Wooo Boy! Read several threads in the EGR valve...... Car runs just fine. Idles fine, gas mileage it fine, just the CEL light is on all the time


Ill check the EGR valve, this may be just a coincidence, but my Prelude did the exact same thing when I went test pipe, & disconnecting the battery for 20 seconds & resetting the ECU cured it & it hasnt come back. The Accord is being more persistent.

Yeah the EGR code can be a PIA to get straitened out.

[Blainethemono]

Well, it appears the yellow wire comes straight from the interior fuse box to the CEL with a single connecter between them.
.

[ShiRen]

Yeah? What did you expect there? The ECU turned the light on.

[Blainethemono]

If I traced my wires correctly if I remove this fuse, the CEL goes out, but the ECU will still flash codes

[Blainethemono]

Yes, thats what Im trying to achieve. Disable the light only. Car runs fine.... I guess I could just put a black piece of tape over it lol
Wiring diagram shows that the yellow wire only powers the CEL, & NOTHING else.