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Freaking Knock Sensor Connector Location S40-V40 2004

I'm hoping this is an easy one to solve.

I'm doing some semi-major maintenance on my 2004 S40 (1.9 turbo,early model), and in the process I disconnected the harness end of the knock sensor (the one closer to the transmission) to give myself some more room to work. I'm usually pretty good about marking connectors, taking pictures, etc, but I slipped up on this one. I'm ready to put all the pieces back together, but I can't find the matching connector, and I'm at the point where I'm about to start undoing the work I've already done because I think I buried the connector somewhere in that mass of vacuum hoses and connectors that lay across the bell housing.

A little more detail - I'm replacing input manifold gaskets and all associated seals for the parts that you have to remove to get to that. I also replaced the turbo (it was getting whiny). So looking at the engine from the front towards the passenger compartment, I cleared everything out of the way on the front left corner and the rear right corner.

Also, I did NOT disconnect the knock sensor from the block, just the harness end to make some room for my hammy hands to work. I've crawled under it, laid on top of it, felt around in places I could not see...I cannot find the other end of the connection. The "lay" and the length of the cable seems to indicate the the connector is somewhere close to the firewall, but it is hiding from me.

I've attached the new turbo, and anyone who had done this will testify how freaking hard that ONE nut can be to get to, and I don't want to disconnect all that stuff again to find this connector.

Can anyone who has done this, or who hasn't but has a same model S40, help me out? The cable comes out from under the manifold and goes somewhere towards the firewall. I've attached a pic of the female (?) end of the cable.

Thanks in advance.









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    Freaking Knock Sensor Connector Location S40-V40 2004

    Resolved, I think.

    I mentioned that the engine in the car was a swap, and that I didn't do the swap. After tearing down 2 other engines in my local PullAPart, I found out the 1.9 only has 1 knock sensor.

    The best explanation I can come up with is that the guy who did the swap carried over the other sensor from the swap engine and also connected the cable from the sensor that was on the original engine. There's a location up higher on the block where the sensor appears to fit, but that should actually just be left empty.

    I swapped out the cable connection on the sensor strip, and (magic), my misfire codes cleared up. Who would have thought :-(








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    Freaking Knock Sensor Connector Location S40-V40 2004

    My '01 should be the same. I don't remember seeing that particular connector.

    I can take a quick look at the rats nest.
    You say it's wrapped in the harness that goes over the transmission? Ugh.
    I replaced the transmission a few years ago and know what a mess it is to see or get to anything.








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      Freaking Knock Sensor Connector Location S40-V40 2004

      Here's a little more info. The engine isn't the original one that came with the car. This 1.9 came out of a V40, and I had another guy install it because I didn't have the time to do it myself, so I don't have a clear memory of what knock sensors were on the replacement block. I asked him if he remembered but he did't recall either.

      I called a local Volvo dealer yesterday and their parts tech told me that the original design of the S40 only had one knock sensor, as opposed to the 2 that are on the block I have in the car now. But weird of weird, this block has one connected just behind the starter, which is connected through the harness to the junction strip on the firewall, and another about 6 inches up near the top of the head, which is the one that isn't connected.

      This is the early (1G) model, and there isn't a lot of good documentation on that block that I've been able to find. I am not assuming that the parts tech is correct (he didn't really sound too interested in researching this), but I am reassembling the engine and if no one else has the answer will go to the junkyard this weekend to see if I can find another one and take it apart to see what I can find.








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    Freaking Knock Sensor Connector Location S40-V40 2004

    Find the Volvo wiring diagram (TP*****...) for your year and model.
    There should be help with the sensor location, connectors and harness

    I looked in the 2007 5 cyl wiring diagram and the knock sensor 7/24 plugs directly into the ECM pins A46/A20.

    Bill







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