There’s 0.2ꭥ between this green and this red wire which is almost a short circuit (the ecu confirms it). The shape below is because of the heat of the engine causing the plastic to melt
A good knock sensor needs to be a new knock sensor of a brand a repair shop would sell otherwise the car isn’t insured so which results in costing over 300€. And here’s a compatible one :
This is likely due a small contact between the 2 metal part of the plug inside (which should be fixed by inserting a small piece of paper between them). The problem I don’t know how to open it while being able to plug it inside the knock sensor again after.

This part is not sold on retail. Even for a repair shop. And local scrapeyards aren’t selling it there. So the only way to fix the problem is to keep this plug.
What would be the step by step detail for inserting a small piece inside preventing the short circuit while still ensuring it will stay plugged whatever the road is ? I mean a creative solution for opening it without breaking it too much.

  • 2
    This question probably belongs on our Electrical Engineering community. Questions on Lifehacks are much simpler, and allow for multiple creative solutions, like "How can I put sunscreen on my own back?" The Lifehacks community doesn't really handle questions that have just one correct solution that should probably come from an expert (like an electrician). May 5, 2019 at 13:53
  • @BrettFromLA this is defintely about lifehack since it s about not changing it. Question edited. Other websites would close the question as off topic because the ansswer would be just buy a new one even if it s impossible. Just replace the word plug with box if it s not enough clear. May 5, 2019 at 14:22
  • What's the make and model of this vehicle?
    – Stan
    May 5, 2019 at 17:34
  • @Stan this knock sensor plug is common to all models of Toyotas and Daihatsu produced between 1995 and 2016 As well as some Citroën and Peugeot. May 5, 2019 at 17:38
  • Please show a picture of the socket that the plug plugs into. I get the feeling that replacing both the plug and socket is possible, and appropriate in this situation
    – Caius Jard
    May 8, 2019 at 7:51

5 Answers 5


Here is the way I repaired my vacuum cleaner polarized power cord moulded nylon and rubber plug that needed repair.
A replacement (from Sweden - I'm in Quebec, Canada) was over $110 plus 15% provincial sales tax.

  1. Cut or break the plug in half to expose the interior of the plug.
  2. Make the repair(s) you want.
  3. Test the plug to see if it works.
  4. Epoxy the original plug parts together.
    Ensure that the epoxy you use does not conduct electricity, can withstand the heat from the engine block, and is a good bond for the kind of plastic used for the plug.

Tip: Before you work on the only plug you have, increase your skill and knowledge with other kinds of plugs and parts for practice.

Note: Despite your personal experience, Paper is not an electrical insulator so much as a simple physical separation. Any moisture will turn paper insulation into a good electrical conductor. Your dry laptop battery sitting in your home is not a good comparison for the hostile environment of a working internal-combustion engine. Just saying.

Good Luck.


Plugs like that are usually molded single piece items, the wires are fitted by having a springy tab sticking out of the connector end of the wire. As the connector end is pushed into the plastic plug the tabs spring out and grip the plastic, preventing it from coming back out. You can remove them again if you can identify where they are and push a fine flat bladed screwdriver down the back (where the wire goes in) of the plug, aiming to fold the spring tab flat so it is no longer against the plastic

Take a look at this picture of a molex connector in component form, for a better idea of what I mean:

enter image description here

This picture features 4 connectors (two male pins, two female pins) and is intended to allow 2 wires to be connected and disconnected. The connectors are paired up for shipping but in use would be detached from the metal bar that has a rectangle and two circular holes in. They would then be crimped onto the end of a wire, and then those two small metal pins sticking-out (creating a Y shape) are the tabs that hold the connector into the plastic block. Removing this connector from the block again requires the pins to be folded flat against the body of the connector, the connector slid out, and then the pins folding out so they will grip when reinserted

All that said, I strongly recommend you consider replacing your entire plug and socket with something that IS available in your country. The plug you've pictured SHOULD be available as it will have been used on countless different makes and models of car. See if it has any manufacturer name on (not necessarily the brand of your car)

Edit update:

I'm not entirely sure why you're posting on lifehacks, as you've just added information to your question that seems to imply that anyone jury-rigging any kind of thing that is not an original car part as approved by the manufacturer will instantly void their insurance (yet you've also commented to imply that a home-made repair has been carried out on your car before - confusing; have you been driving uninsured all this time)..

That said, when i recommended "making a plug" - spray the socket full of some lubricant, attach two individual wire spade connectors to the ends of the wires, then push them onto the pins inside the socket, fill the entire socket with silicone sealant (like what you put round your bath) and let it set - you'll now have a new plug, molded to the shape of the old, with two connected non-shorted wires embedded in the cured silicone. Old socket, new plug. The lubricant spray should stop the silicone sticking to the socket for easier removal

  • Because of the local mindset and local labor costs, the connector is available only with a whole car. About the current one, the car come from Italy. May 8, 2019 at 11:30
  • Not really sure how that comment relates to my answer..
    – Caius Jard
    May 8, 2019 at 13:25
  • I strongly recommend you consider replacing your entire plug You have the answer : it’s not available. I suppose you understand the required socket must be compatible with engine body. May 8, 2019 at 13:43
  • You're quoting me out of context I think - i'm proposing to replace both the plug and the socket. If the socket is part of the component then either replace to component or re-shape it so an alternative plug will fit. You can consider making a plug but you also seem to be saying that "if any car has anything replaced that isn't an original component then it isn't insured" - it seems unlikely to me, but perhaps you really do live in such a draconian country. How about buying a plug from another country? What country are you in?
    – Caius Jard
    May 8, 2019 at 13:51
  • Local insurances don’t allow peoples to mend their own cars. So the part has to be one a repair shop would buy (otherwise the contract can be voided in case of an accident). Not this is against the law to allow it but simply no insurance do (this is something needing to be created). In response they are association based repair shops where you need to pay a yearly subscription which will end up cost you more than going to a professional whenever you just need it. Buying a plug from a foreign country wouldn’t be a problem at all. But how to do it ? I’m really far from the nearest frontier. May 8, 2019 at 15:09

You might have to change both the receptacle and the plug with something similar and compatible.

Before you go to that extreme, if you can't by a new replacement, buy a used one from a junkyard or recycling operation as the replacement. You might have to buy more than just the plug; but, if the used assembly includes the plug, you're good to go.

If that doesn't work you'll be faced with making a mould of the plug and working to refurbish the one you have. Possibly, 3D printing might be the way to go at this point.

Paper is not an electrical insulator so you'll get no joy from that solution.

If local centres don't have the part, you'll have better luck broadening your search until you locate one.

As a hack, how much does a used engine (reclaimed from a collision) cost? After you get the part you want resell the engine parts you don't want to a junk yard.

Also, communications between junk yards is pretty good. $weeten the request to your junk yard and let them find one for you online by sku/part number. (I bought half a car to get the rear hatch assembly for a station wagon and returned the unwanted parts for a partial refund as the "dealer" didn't want to expend the labour for my part; but, gladly bought back the rest of the hatch.)

  • No That’s an effect of the picture (the plug look different in reality than on the pictures). There’s no corrosion at all but only copper. The shape is because of part of the platic olt because of the heat of the engine. May 5, 2019 at 17:26
  • @user2284570 Well it's not wrong. It just doesn't apply to you : ) No harm done. I can edit my answer almost as fast as you can edit your question. Good.
    – Stan
    May 5, 2019 at 17:55
  • The problem is because of local labour cost it doesn t worth to lift the car just for a part as cheap as that one (in a scrapeyard). May 6, 2019 at 19:09
  • @user2284570 That's the point. It's not the cost of the part that is the issue. It's the cost to you of NOT having THAT part. Remember the (very) old adage, "For the want of a (horse) shoe, a war was lost." Things add up. If you can't use your car which is worth something because of a tiny necessary part which is worth many times less, you lose your use of the whole vehicle.
    – Stan
    May 6, 2019 at 20:43
  • I just mean this is Scrapeyards which refuse to spend the required man hours above what they could get for selling that part. And in my country’s mindset rules are rules. If a small item should be sold for a specific price, you can’t ask a higher price that would allow getting the job done (I mean the boss of the scrapyard will also say NO too for that case). In general (this is not just about cars) if a set of business rules prevents to do something in a very stupid way, then they are still dumbly enforced even if there’s nothing in the law risking to prevent it. May 6, 2019 at 21:19

If it were mine, I'd be tempted to take this as a good reason to trade in the car.

Seriously, if you have to buy a major wiring harness to replace a connector like this, which is positioned so engine heat can degrade it, the cost to repair is something best passed on to a used car dealer (because they wouldn't be the least hesitant to pass a similar defect on to you). I'd also avoid buying the same brand as a replacement.

Failing that, you might see if you can buy insulated slip-on terminals that you can crimp onto the wires, and that will fit the terminals the melted plug connects to. You'd have two terminals instead of a one-piece latch-in connector, but electrically, it should be the same.

  • Yes. Your second thought (failing that,…) was my first suggestion; but, the OP didn't like the substitution option. Wanted repairs. Your extra detail might help him solve the problem.
    – Stan
    May 7, 2019 at 17:12
  • By the way, Thanks for the down vote for striving to find a solution. Maybe someday someone will return the favour to you. : )
    – Stan
    May 7, 2019 at 17:15
  • @ZeissIkon the car degraded the connector only because of the way it was set up. I mean incorrectly. May 8, 2019 at 11:48

If you cannot replace the plug or the harness it's attached to, you will have to operate on the plug to access the components you feel are problematic.

There's some kind of snap clip on the top. Stay away from it. If you break that, you will lose the ability to hold the plug inside the receptacle. (Is this correct? Please verify. You might also edit into your question a picture of the receptacle for a better analysis.)

All of the ridges and flanges on the part are for alignment, access (to grip it), or for part integrity (strength against splitting).

Disclaimer and notice. Anything you do to this plug now will compromise the part. It might fail before, during, or immediately after your "repair." Let's assume that you are a careful and skilled worker and that you have the knowledge and proper tools to do what I'm going to suggest.

Now, here we go.

  1. Flip the plug over and work on the bottom of the part.
  2. Carefully drill an access hole where you suspect the "short circuit" has occurred to expose the area for work. Don't drill through the plug. You only want access as far as the conductors. Make the smallest shallow hole you can since you can always make the hole bigger.
  3. Separate the conductors physically and put a heat-resistant physical separation between the conductors.
  4. Test the plug's conductivity.
  5. Reseal the access hole with a specific material best-suited for the environment. This will probably be some kind of epoxy. Sugru is a moldable self-curing material but is only suitable for low voltage insulation - it is suitable for the voltage but you will have to do research to ensure what you finally use will remain stable for your application.
  6. Put the part into service.
  7. As soon as possible, find a replacement using the internet, by contacting the OEM supplier (research), continuing to scavenge used/damaged reclamation locations.

Work harder improve negotiating with people around you who have a rigid mind-set. Learn to be more flexible by ignoring negative attitudes. Lose the "can't," "won't," "don't," "refuse," "impossible," and "only" terminology that pervades your question and comments. Get the opinions of knowledgeable people. B+ (Be Positive ! ! !)

This will be my last attempt at trying to answer this question — There's my bus. Gotta go!

Good Luck!

  • Ici ce n’est pas le Canada ni l’Afrique ni la Belgique : les gens sont rigide et ne négocient pas c’est comme ça. May 7, 2019 at 16:42
  • Positive attitude won't fix the car. Feeling better about the situation won't fix the car.
    – Zeiss Ikon
    May 7, 2019 at 16:46
  • @user2284570 Oui, alas, c'est évident! Mais, je vous offre les meilleur réponses que je peut! Bonne chance, mon amis. Soyez bien!
    – Stan
    May 7, 2019 at 16:53
  • @ZeissIkon Ha, ha. It's about a flexible, problem-solving attitude not the cosmic forces. Now that you mention it, I'm looking forward to your brilliant problem-solver answer?
    – Stan
    May 7, 2019 at 17:05

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