Broken knock sensor wire 97 Outback

[dasaan]

My 97 Outback CEL was on for a knock sensor, so I bought the part and went to change it. While attempting to disconnect the sensor the male end from the harness broke off still attached to the knock sensor female connection.

 

My question is what I should do to repair this break? Can I just have the old male connector spliced back onto the wire harness? Are there any specifics of the wire that might be important? Can one find the whole wire back to another connection or the ECM and just replace it? Or will I have to do what the dealer says and replace the whole wiring harness?!?

[The Dude Abides]

Kinda off topic a bit but what symptoms was the car doing other then the check engine. Stalling, chugging, whatnot.

[dasaan]

Nothing really. It was a little slow through the range acceleration-wise, but I just use it get around and only noticed on the on-ramp to the highway. I was just replacing the sensor to clear the code and meet NY inspection standards.

[griffenrider]

I wouldn't think you'd need to replace the entire wiring harness, you should be able to splice the wire together. Knock sensor signals should be pretty clean though, so make sure you get a nice tight splice and solder it cleanly, don't just wire-wrap and electrical tape. Not sure how far up the wire the break occurred, but if it isn't enough to do a good splice: once you get male end off your old sensor, you should be able to open up the plug and solder a new wire to the contact directly. You'll get as much slack as you need to make the repair.

 

Make sure you disconnect the battery AND remove fuses before playing with naked wires though!

[Gene J]

A bad knock sensor will cause the car to be sluggish and it will get a bit poorer mileage as the spark timing is pulled back.

 

If you never stomp on the gas you would never notice.

Edited December 30, 2009 by Gene J

[idosubaru]

symptoms can vary, this isn't black/white, they car run for years with this code with little noticeable effects or they can be nearly undrivable...and of course anywhere in between.

 

just splice the wire back together. i wouldn't worry about it too much but i wouldn't hack it either.

[dasaan]

I have driven with this code since I bought the car over a year and 25,000 miles ago, but I moved to NY so now I have to clean it up to pass inspection.

 

I am glad to hear that I can just do the splice. I thought that the change in resistance might affect the system too much and the CEL would still stay on.

[dasaan]

Final note.

 

I had the wire spliced to repair the connection, and the knock sensor code has gone away. I had two other codes for the catalytic converter and a Subaru specific problem that cleared with the knock sensor code.

 

All set for NY standards.

[Cougar]

The wire connection is just that, a connection. That means you can connect it any way you want to just as long as the wire connection is good. Which means there is no added resistance to the circuit at the slice point. The circuit is a pretty high resistance circuit anyways so even if the splice added a little resistance somehow it wouldn't make a difference.