I just did my Civic b18c swap back to a Sohc vtec d16y8. Both engines never had check engine lights on. P0131 code came on and i reinspected the wires and it looked good. I thought maybe the 02 sensor got damaged from storage over the years so i took my good b18c1 o2 sensor and rewired it with the civic connector. same code

the code is o2 sensor low voltage in bank 1 sensor 1. I rechecked my a few times wiring and even tested a second sensor and its still throwing the code almost within a min or two once its warmed. I tried putting in a different ecu thinking possibly i damaged the old ecu in storage. still no luck anyone dealt with this code before and some easy solutions.
I check for exhaust leaks and vacuum leaks that causes a lean low voltage but nothing obvious yet on it.

any suggestions on the next step? no time yet to get it hooked up to my works scantool to see o2 readings.

 

still no solution yet...any ideas?

 

might have a bad 02s try to check the resistance on the 02s touch the 2 black on the 02s they should be 8-up ohms

 

I have replaced the o2 sensor with a new one...OEM style and even rewired my old GSR motors 02 sensor and still same code. today i tried to solder the wires to make a good connection and code still comes on.

one reason i thought it may be a connection problem was because of the three weeks i been messing with it on my days off....i was able to make it one whole day without the code coming on with driving. Today after soldering the wires the code comes on instantly?

 

still no help?

 

I have been trying to do process of elimination with parts and still cant find anything. O2 sensor wiring has been resolder, tried to replace o2 sensor, retorqued exhaust manifold incase of exhaust leak, put in a spare fuel pump in, put more gas since the car was parked for about 1 1/2 months, cleaned fuel filter, added injector cleaner.

 

are you getting voltage out fo the connection coming from the ecu? get a wiring diagram and go at it...

 

o2 readings on scan tool shows the sensor is switching properly...

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NationsMostWanted &raquo;</TD></TR><TR><TD CLASS="quote">o2 readings on scan tool shows the sensor is switching properly...</TD></TR></TABLE>
Does the scantool you have allow you to take a snapshot using the cel as a trigger?

 

such as freezeframe data showing the condition when the cel is first set?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NationsMostWanted &raquo;</TD></TR><TR><TD CLASS="quote">such as freezeframe data showing the condition when the cel is first set?</TD></TR></TABLE>
That might help. A 30second snapshot would be better though, if it has the ability.

 

since I have gone thru the parts swapping already LOL what do you suggest might be the cause? I feels its a intermittent wiring issue somewhere.

 

i finally gave up and sent it to a electrical shop. after the first hour of 95 bucks they told it they wanted to charge me 400 bucks to shorten my o2 sensor wires. i said no and i took the car home and told them ill resolder it with the connector and bring it back. once i got it done i got new codes...p1298,0135,and 0141. im hoping this is going make the issue easier to solve.

 

well on that 1298 you got a ELD electric load detector..

0135 and 0141 are both heaters on your o2 sensors..you did something wrong..

 

yea the fuse got shorted no clue how but i replaced the fuse and no cel light yet. no i wonder if my old p0131 code will come back.

only thing i did different is i used the original wires without extending them and soldered them....i dont think that could be any different than me extending the wires and soldering still?

 

whats year is the car?? sound like you had a blown fuse #15 7.5 fuse the cause for this is the harness that runs behind the intake manifold by the bracket that goes from the intake to the block is short cause fuse to blow. you need to inspect the wiring back there where they usualy rubb together is at the junction connector thay just need to be repaired and taped up.

 

That fuse blowing is a common problem and like stated ^ its caused by the wires shorting under the intake manifold. There's a service bulletin on it from honda.

 

very odd what else other than the intake manifold rubbing causes this same fuse to blow?

The fuse keeps blowing on me i tried to zip tie the harness up and it still didnt help. whats odd is this is occuring now right after i fixed the other low voltage issue.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by NationsMostWanted &raquo;</TD></TR><TR><TD CLASS="quote">very odd what else other than the intake manifold rubbing causes this same fuse to blow?
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Actually the wires rub through on the intake manifolds brace. You should be able to pull the brace off and see the wear if that's waht's going on with it. But it's kind of odd it didn't do it till after messing with the wiring.

 

yea is the wires rubbing the actual harness or is it the wire from the two fat empty connectors? i havent unbolted the brakcet yet which i will

 

you sure you didn't mix up the 02 wiring when you soldered the longer wires?

also, is this the primary 02 or 2nd 02 sensor thats giving you problems?

I dont know if this would fix the problem, but perhaps running an 02 cel light eliminator might fix the problem. Blox and T1R make these.

 

P0131 low voltage is a sign that O2 sensor is reading a lean condition. If wiring is okay then check for possible causes.
1) Exhaust leak ahead of the primary O2 sensor.
2) Engine is running lean becasue of tuning, vacuum leak, low fuel pressure, etc.

First check for exhaust leaks which is easy to do, exhaust mainfold gasket or mainfold to a-pipe gasket leak.

If that checks out okay, check for the engine running lean.

Question: Do you have your VAFC removing fuel? If so check the tuning.

 

this is not the problem anymore...

 

well i took off the manifold bracket and saw no signs of wires rubbing...put tape around the wires anyways to be safe. once i put everything back together and back out off my driveway the light came back on and fuse is popped.

i do notice that the fuse is tending to pop when i back out of or onto my curved driveway right when my exhaust rubs....i wonder if its something in my secondary o2 sensor thats causing it short. i havent had the time to put it back up to check again today.

 

i hvae done all of the same things that you have gone through and i am still running the cel. i thought it may be running len so i tossed a walbro 255 in to see maybe if the fuel pump is bad. gonna see if i can find an adjustable reg too but . on a seperate note,after i got the CEL again i decided to think outside the box and replace the gasket on the distributor cap. car is running a little rough probably because im running 50+psi of fuel at idol but since i replacec gasket no CEL keeping fingers crossed