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Discussion Starter · #1 ·
I have an EPC light popping up every now and again, for seemingly no particular reason, then is goes out of its own accord. Pops up kinda randomly...I have tried to induce it by jumping on the brakes, accelerate hard, driving at 60 with high revs. Sometimes starting, it will be on, reverse out of my drive, and it will go off.
Snap-On diag tool shows historical P0327 and P0328 - which is the knock sensor. No other OBDs show anything. If I reset faults with the diag tool (even a normal OBD)...the light normally does go off, seemingly (odd....seeing as no faults detected)
So...went and bought a knock sensor and what I got does not seem to match what is at the back of the engine, where I thought the knock sensor was located ( under a little heat shrouded piece of material). Is this the knock sensor ? I didn't remove it, but did disconnect the wire, and a thimble full of water seemed to be "stored" in the plug, and hence thought "ah, that'll be why I was getting a random EPC....it had water in it". Drying, and spraying contact cleaner, reassembling, however, didn't seem to fix the EPC error
 

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Discussion Starter · #5 ·
Those pics are awesome...thank you. Where do they come from ?
So, any idea what the sensor is at the back of the engine then (in my case, the one with water in!) ? Has a little heat protective material clipped around/covering it ?
 

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Probably either the engine speed sensor or cam position sensor?
 

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Those pics are awesome...thank you. Where do they come from ?
So, any idea what the sensor is at the back of the engine then (in my case, the one with water in!) ? Has a little heat protective material clipped around/covering it ?
I work as a parts advisor in a main dealer, so these pictures came from ETKA

List of engine sensors:

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I would not think so, as this is on the block itself, rear side of the engine, midway down, in the middle.
indeed - a lambda sensor will always have one end poking into the exhaust stream (ie not into the block, head, or bell housing)....
 

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Discussion Starter · #12 ·
Well, I changed the knock sensor with @lupogtiboy pictures.....pretty easy, and did NOT need to take any of the shields off - from under the car, you can get a 10mm spanner in there and replace pretty easily. Hopefully, it fixes my intermittent EPC light.
I have attached a few pics of the "other" sensor, which does not seem to show up anywhere (the one that I popped the connector out of and had a thimble-full of water come out of). This "sensor" is held in by a single 10mm bolt, covered with cloth heatshield (alike the knock sensor), but is higher up on the block. Wish I'd have taken the heat cloth off of it to get a better picture (but it was a PITA to put back on!). I am more curious than anything else, as to what it is - is it the lamda sensor pre-cat, as @Reiver states ? Can't see why it would have water in the plug/socket !
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Discussion Starter · #13 ·
and annoying...the EPC light popped back on this morning, after a weekend of it staying off since the knock sensor replacement 😒
I am now at a loss what to check
 

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Not sure, but I think the other sensor above must be the pre-cat lambda, as the exhaust manifold is part of the head.

Apart from the error code and dash warning, does the car run well?

Something could be making it run leaner than can be dynamically compensated for, and the engine is at the point of knocking (low fuel pressure, bad injector?), or the timing is a bit out (cam angle sensor?).
 

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Discussion Starter · #15 ·
Apart from the error code and dash warning, does the car run well?
When the EPC light is off.....absolutely fine, no issues whatsoever.
When the EPC light is on....revs are limited to about 4000rpm. No other noises or symptoms. The EPC light goes off as randomly as it comes on, even when driving along (no engine shut off), and when it goes off, it happily revs above 4000rpm again
 

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My money is on a fuelling issue or cam pos. sensor.
Easy to say "my money" though, in this case!
 

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Tinker at a few old cars I have, no mechanic and only really have a rough idea about the very specific things I have to look into on occassion.

Reading about the knock sensor appearing to work, then not, reminded me of something I read recently relating to MK2 Golfs.

Haven't double checked this so may have misremembered but the knock sensor on those needs to be very accurately torqued (to 10Nm?), does that say the G61 is to 12Nm at the bottom of post #4?

Maybe you already did, but might be worth checking again?
 

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Discussion Starter · #18 ·
My money is on a fuelling issue or cam pos. sensor.
Well, maybe. I am pretty sure the (water ingress) sensor I located above the knock sensor is the cam sensor, as a pic from the internet shows this:
Household hardware Magenta Auto part Titanium Tool

and that is apparently p/n 04C907601 - looks very very similar to my pic in post #12, and what I remember with the heat cloth off. However, the pic that @lupogtiboy kindly sent, both the cam sensors are on the top of the engine, unless the picture is actually a little off set. It could be, as the knock sensor kinda looks like it is on top too. Confused. Might be worth trying to change, I guess.....wonder if the input and exhaust sensor is the same p/n ?
 

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Here's a view of the rear of the engine with sensors in place. There are two cam sensors, inlet and exhaust, top left on the picture. knock sensor at the bottom. Not sure what the other sensor is....

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Discussion Starter · #20 · (Edited)
Another great pic. So, this is my water ingress one:
Gas Engineering Auto part Automotive super charger part Machine

I am not saying that is the cause of my EPC light, but it is suspicious. What the heck is this ? Crank sensor ?
Are the two cam sensors (top left) the same part number ?
 
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