lushy

Yeah, that picture was taken at a WW2 military fort that looks over the Halifax harbour in Nova Scotia.

I made a break through tonight! last week I traced those ground wires and found one was cut, so I got them all re connected but it didn't fix my problem. So, determined that I had figured out all of the wiring, I went out on a limb and bought another front oxygen sensor and VOILA, so more lights! thanks for all the help, esp OB99W. Here are a couple pictures of my project for your viewing pleasure!

Hey, new info, tonight i checked some other grounds on the ecu and found that pin A7, a15, and c1 were getting a weak ground signal, when i hooked up the grounds to a good body ground, i got rid of the p0031, but in turn i got a p0134 (02 sensor (rich or lean)) the car is running rich (strong fuel fumes in exhaust). This must be some form of progress!

the sensor is for a wrx, they were way different. Thanks for all the help! i will let you know what the problem was if i ever figure it out, lol

brand new oem denso sensor

The swap did involve alot of cutting and splicing. i just checked the white wires while starting the car, and as soon as i turn the key over it goes from 12V down to 7V (for about 5 seconds) then shoots back up to 14V. so the ecu is trying to ground out the heater circuit, but doesn't seem to have a strong enough ground source maybe?

ok, engine running and up to temp o2 signal wires 19 and 29- 4.3V o2 heater wires (white) - 14V each ground pins 8 and 9 - 0.04V black and red wire i inquired about is getting 14V Then i checked continuity form white wires at ecu to o2 sensor plug and its the same wire! Then i checked the grounds to ground and they were .4 ohms each!

wow great detective work! this afternoon after work, i am going to get the car running and up to temperature, then do a voltage and ground check. Thanks for all the help so far! i will post up later how my checks turn out! coming off the main relay for the o2 system, there is a BR wire that goes to pin E10 (seen on page wi-84, section 17) what should i be reading at that pin? 12V correct?

so looking at the diagrams you provided, if you look under section 17 "engine electrical system" the very first diagram shows the o2 sensor circuit. there it is saying that the signal wires are e19 and e29 the shield is e18 and the two white wires are e4 and e5. the "e" connector on this drawing is b84. i won't get to try the latest suggestions until tomorrow night as the car isn't at my house. The 3.4V was when the engine was cold, ignition was on/engine off taken from the sensor's plug while the sensor was unplugged. The 12V was taken when engine cold, ignition on/engine off taken from the back of the ecu plug (still plugged in) and also taken from the sensors plug while it was plugged in. i did notice one more thing, the shield (pin e18) is connected to the ecu via a yellow wire, on the engine side it stops 6" before the plug and isn't connected to anything. I really appreciate all the help, my brain is mush trying to figure this out. let me know if you need anything else clarified.

ok, so the 2 white wires are reading 12v at the ecu when everything is hooked up and ignition on. there is no change when i rattle the connectors.

neither my b137 nor b134 connector look like that The harness came out of a 2004 wrx (non sti) i can't upload attachments, maybe i need to have a certain number of posts first?

my 05 manual says that wires 2&3 in b134 are yellow and yellow with blue... my two heavy gauge white wires are in b137 pins 4&5. If i recall correctly all the o2 sensor wires are in b137

so there are 5 connectors that go to the ecu, do you know the connector number for "a" is it B137?

Hey all, I recently finished putting a 2003 wrx engine in a 98 RS using the wiring harness from a 2004 wrx, the only snag I am running into is the front O2 sensor. I am getting a P0031 code, I changed the sensor and it didn't fix the problem. I measured the voltage at the connector and got the following: Small white wire-4.7v Small black wire- 4.7v Large white wire- 3.4v yellow/red wire- 12v I remember reading somewhere that there are two wires for the O2 sensor pinned out in the ECU differently between the years 2003 and 2004. Because I am running the 2003 ecu with the 2004 harness, this could be my problem, but I can't find it again to know which wires to change. Any help is greatly appreciated!