andy24

i went to test smog my car and they ob2 wont read. so i failed. i also used my scanner and it wont read. does any one know why the ob2 plug wont communicate with the scanner?

forcefedferio

are you running a different ECU? obd1 perhaps? the wire that communicates between the DLC and the ECU is called the "k-line" and is a blue wire with a white tracer, if you answered my first question with "No" then i'd start there.

Former User

Check whether fuse 43 under the hood is blown:

andy24

no im sure its a ob2. my brother smoged his car with the same motor then we swapped it in mine. his passed cause his ob2 read. all my fuse are there.

waaBAAH

your fuses being "there" and fuses being "good" are two diffrent things.

check the wire inside the fuse and see if it is connecting the sides.

andy24

all my fuses are good except for the power window. i dont think the power window fuses would affect it.

waaBAAH

did you check both underhood and underdash fuse boxes?

obd2 connector gets its power from one of those fuses.

if this gets bumped tomorrow i will look at a diagram to see where your port gets its power from while i am at work

civic_driver

Yes, motor, but are you using the same ECU your brother used and if not, you probably should.

Utzz

96-00 Civic's: Fuse 43 (under-hood fuse box, 7.5A) is what powers the DLC.

Also note that "OBD2" JDM ECUs do not communicate with USDM OBD2 scanners...since it's not really OBD2. You didn't list what you're using, so I figured to throw that out there.

But like civic driver said...the motor might have passed smog but are you using his ECU too?

andy24

yes im using the same motor harness and ecu, and its not a jdm ecu cause its a cx motor. this was my stock motor so we are just using it to smog.after the smog im goin to put in my b serious. could there be a electrical shortage?

Utzz

There could be an electrical open too. My meter leads don't work so well through a PC monitor...so you're gonna have to use yours to figure that one out. Either way, there aren't but like 4 wires (maybe 5) that go to the DLC.

Pin 8: Red/Wht - Battery voltage
Pin 12 & 13: Blk - Ground (goes to G401)
Pin 15: Blu/Yel...which then plugs into C131...and out of that connector (pin 21) comes a Lt Blu wire that goes to C8 of the ECU.

This wiring info is for the 96-98 Civic's. The only difference between them and the 99-00 is Pin 15 of the DLC (still Blu/Yel) goes straight to the ECU (A21)...no intermediate connector.

andy24

thanks for the help finally got it fix

Davus

What was the issue?