Rep Power: 0

So I picked this '02 Civic up from the insurance auction and it needed a rear door and later I found out it needed a head gasket. Got that all squared away and the car runs great except it keeps coming up with a P1259 for VTEC failure. I made sure oil level is good, I am using 5w20 just like you are supposed to, oil pressure looks good and all that. Before doing any troubleshooting I went to the junkyard and picked up another VTEC solenoid and had same exact issue, so I think it's unlikely that the problem is with the solenoid or pressure switch.

I put the original VTEC solenoid back on and starting going through the troubleshooting steps in the manual, and #14 is where I think I found the issue...



I unplugged the connector like it said and I DID get continuity between #9 and body ground. It says to "fix the short" in the wire. Not sure what to do now... Replace the wiring harness? Can I just run a wire from the connector to the pressure switch? Seems like that would be a hell of a lot easier.

I'm open to any and all suggestions... TIA!

 
Rep Power: 119

There is a separate oil sender for vtec.
When the solenoid opens, that sender is supposed to go low as the oil pressure is supposed to drop.

Maybe that’s the part the failed or the harness is somehow shorted. Indeed you can run a separate wire, but more likely it’s bad sender.

 
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I'm not sure what you mean about the "sender". There is a solenoid, and there is a pressure switch. Did you read my original post? I did the troubleshooting and it shows there is a short somewhere between B9 and the pressure switch. No guessing, that is the problem. I just want to make sure that running a wire from B9 to the positive side of the switch will fix it lol.

 
Rep Power: 119

Sender in this conversation = VTEC oil pressure switch.

Please understand this, there is practically no way you have a short to ground in a Honda engine wire harness.
Sure one of the previous owners may have decided the harness doesn’t look right and “put a screw” thru it...

Being that you unplugged and “tested” the sender, the more likely scenario is you swapped connectors when took the head off and that’s not the right connector on your VTEC oil pressure switch.

 
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I don't think that's the issue. The pressure switch has a specific connector I don't think there are any the same size near it. I will double check it though. And wouldn't that cause a second code for whatever it was switched with?

 
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And how is there "practically no way" that the harness isn't damaged in some way? I mean, it's almost 20 year old copper wire. Anything could have happened to this car (although the VTEC did work before I did the head gasket, pretty sure).

How is this possibly the wrong connector?

 
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OK so I did so an overlay and replaced that wire and made some progress! I made it to like step 29 in the troubleshooting and then it told me to fix the short in the wire going to the solenoid... Uggggg...

I replaced it and went for a road test, still threw the code.

Starting over in the troubleshooting procedure and seeing what it has me do next!

 
Rep Power: 119

To be exact, “practically no way you have a short to ground in a Honda engine wire harness.”

Key word being short to ground..

That would require 2 wires to be broken inside the harness at same place and touching each other or a screw driven through one wire and into the chassis.

Indeed, in that photo you seem to have it plugged correctly. Never underestimate the creative rewiring some users have done though..

 
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I replaced the wires and got a lot further in the steps. Then I think I might have fried my ECM, check out my other thread. :-(

 
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OK I got everything working... I forgot to plug the connector B back into the ECM lulz. Fired right up! P1259 is gone too, so it might have just been a ground issue, but now it has some fresh new wiring too! :-)

 
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Drove it for a while last night and it did throw a P1259 finally. Took a while. I took it back out this morning and tried to get it to fail again. Followed the steps in the manual, ran it at 3k rpm for a minute then road tested. 3 times to 4k rpm in first gear did not reproduce the code. Hopefully it stays off.

 
Rep Power: 195

So I've been having this same code it comes on and goes away without intervention. I did check the oil and it seems fine. Good level. The code pops on and off with new oil and filter. So did you solve your issue? ​

 
Rep Power: 222

Screen on the solenoid may be clogged