help diagnose DTC's from intake spacer/ valve cover gaskets install... :/
 

okay, well i order and installed a blox 5/16 spacer and new valve cover gaskets with no problems. also changed the spark plugs. after all the dirty work was done, i started the car, but forgot to plug back in the MAF, duhhhh. lol i quickly figured out something was wrong, and fixed it. after this initial start up, VDC low track and SES lights were on. so i did the pedal reset on the ECU, no lights, purred like a kitten and i noticed my gas gauge moves much slower now. :biggthumpup:

so after about a week and 100 miles worth or short 5-10 miles trips, SES is back on. i scan it and i get

C1130 which means that the Anti-Lock Brake System (ABS) control unit has detected that there is problem with the Engine Control Module (ECM).

P1815 - manufacturer mode switch circuit

U1000 -U1000 Infiniti - CAN Communication Line - Signal Malfunction

and a P1283 but that was an existing code from installing test pipes. another bass ackwards deal, who has heard of a stinking upstream O2 going out shortly after cats are removed? down streams are reading fine...

anyhow, my first thought is oh ****, but after looking what the codes were, I'm thinking, this a faulty ground. for sure.

i pulled the wiring harness off the drivers side and front of the motor when installing the fresh valve covers.

*on a side note* i did remove drivers side cam position sensor during this. however i did not unplug it.

so i had originally cleaned the grounds with a brass brush wheel on a drill gun, and i believe the only 2 grounds i unhooked were on the timing cover, (3 wires but one ground is a double wire) so after checking the tightness of the bolts i removed and used some sand paper on all surfaces (bolt, brass, and engine block). battery terminals are tight, so a both grounds in the battery compartment.

so i did the ECU reset again, twice today now, and the SES goes out, but after about 1-2 seconds of idling it comes right back on. but from what i could tell from my drive home, there is no apparent drivability issues. i won't get to romp on it to test responsiveness due to a evil little smart drive device that is monitoring me for the next 2 months...

but now I'm puzzled, trying to find a loose or dirty, and probably non existent ground.
or maybe my ABS module or ECU is failing. but i do think one code is causing the others to be thrown.

somebody tell me what the hell I've screwed up this time. :52:

Check your battery voltage.

Go back and check eerrthang you touched.

Don't really have a proper multimeter, but car starts really quick to have a lower battery voltage...

Well I did, that's why I started the thread. Everything is accouned for and in top shape. The only things I can think of as possibilities is having removed the drivers side cam sensor, possibly damaging it, and having removed the wiring harness. I think all wires are grounded/reconnected tightly, but there is also a possibility of a crack or short in the wire somewhere, from all the flexing and pulling and pushing during install. Additionally the ECU could be bad, or a fuse for it, but would I see and drivability symptoms? Or maybe not since its probably staying in a safety loop mode. Or... It could be the p1283 code causing all the faulty circuit codes to get thrown. I'm not sure if buying a new O2 will fix it either. I have test pipes with anti foulers on down stream O2's, so I may have to tune the code out. Speaking of which, is it worth my time and $$$ to get a tune on the car? Hoping you all can help me narrow this down.

P1283:
Faulty Air fuel ratio (A/F) sensor 1 Bank 2 Check wiring and connector pins
- Faulty Air fuel ratio (A/F) sensor 1 heater Bank 2 See below, you'll need a meter. They're cheap...
- Fuel pressure
- Faulty Fuel injector
- Intake air leaks see below
- Faulty Air Flow Meter Check MAF connection, one wire breaks easily in the harness and clean pins with electronics cleaner. Do that with all of them actually.

Check the heater circuit for ~10 ohms to ensure it is not the sensor throwing the code. It is the two white wires I believe.

After that passes, check for intake air leaks by running it and spraying carb cleaner at the plenum the motor will bog if there is a leak.

Sounds like you messed up your sensor during the install or the wiring for the sensor during your other install, be careful man take your time. P1283 is a bitch. Rockauto.com was cheap enough that I could afford to buy all four OEM brand new. I have two front O2's that I know are good if you are feeling cheap.

Edit: I was assuming you were performing the reset correctly, try pulling the negative terminal and holding the brake pedal for 10 seconds then do the re-learn before you tear anything apart. Oh and you should get a tune if you don't have one.

good info. thank you.

but i am a bit confused on the air leaks strategy... how will i spray carb cleaner at the plenum with out creating a leak to get the carb cleaner in? i usually pull the brake booster hose to sea foam the top end. and i know if i unplug the MAF car will fall on its face with any degree of throttle whatsoever.

and I'm pretty sure i was performing the reset correctly. the SES was flashing slow at the end. and when i started car up, no SES light, for about a whole 1-2 sec that is...

update: I've been working on the car a couple hours this morning. i reset the ECU by unhooking negative battery post, and holding brakes. started it up and let run about 10 sec. no light. i think is will get about 100 miles and it will come back. but i think the only code that it will throw is the p1283. the others i believe were due to the fact that i forgot to plug the MAF in after the tearing into the top end. that or the p1283 were causing the other codes as well. going to try buying 2 new upstream o2's, as the car does have 216,000 miles and they are probably the originals. after the going to get set up with the guys down at Z1 in Atlanta, and have the car dyne tuned and the code tuned out.

on second guessing my thoughts, none of these codes showed up for 100 miles after the rebuild. so either the other codes didn't turn the light on and the p1283 did, (is that possible?) and the others were just there as well waiting to be found, or they all got thrown at the same time. i checked the codes about and hour after i seen the light pop on the first time.

i have not tested the ohms of the o2's yet. ill be doing that before buying anything. but to clarify, i test them on the connector pins when it is unhooked from the o2 when the car is running? or just ign on? or?

so all this time ur MAF was unplugged?

No it was unplugged for the first start after rebuild, and I ran it for 1 minute before I figured out it was unplugged. Car was never driven without MAF. You can't drive it without it. It falls on its face with any amount of throttle.

As it turns out the p1283 is back, but that's a whole other situation, that has been long put off. Will get it soon. But all other codes were due to the MAF being unhooked on first start up, and/or a ground. I cleaned all grounds and resets ECU, and they're gone!

Only one bank. Flippy flop the o2 sensors and see if it switches banks