Ford Fiesta 1.25 16v 2006MY - Changing knock sensor

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Sun 30 Jan 2011 10:55
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - 547HEW

Can anyone advise the easiest way to change the knock sensor?

I can see it (just about) but there seems no way of getting to it without removing inlet manifold and all that that entails. (New Injector seals, gaskets, FEAD belt etc etc)

Am I missing something? Has anyone done this operation? I cant find any info in the manuals.

Background: Vehicle is on 120,000 miles so failure of sensor understandable. On a routine check I found that Its setting P0324 and P0325. Tried WD40 on the connector but codes returned. Driver reports no issues, so I guess we can leave it for a while. Which generates the following question:-

Is any damage likely to occur?

Thanks for any replies.

547

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Sun 30 Jan 2011 11:39
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - elekie&a/c doctor

Very unusual for one of these to fail.More likely to be a wiring fault or lack of oil in the engine or an engine problem.I would leave it alone.Can;t see any running issues.hth

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Sun 30 Jan 2011 14:08
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - 547HEW

Thanks Elekie,

Since posting, I checked the resistance across the connector terminals of the sensor. It checks out at 4.9 Megohm cold. Similar to the new one.

It could be that this internal resistor is going open circuit when hot, but equally it could well be a wiring harness fault as you suggest. I think that the resistor is put there only for diagnostic checks, so maybe the piezo generated knock signal is still working fine.

I'm definitely leaving it alone!

Thanks

547

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Sun 30 Jan 2011 14:24
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - elekie&a/c doctor
It is not possible to check the resistance of these.It is a piezo device and it works like a microphone.It listens to any knock/detonation in the engine so that the management system adjusts the strategy as reqd.hth
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Sun 30 Jan 2011 21:43
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - Railroad.

As has been said already knock sensors very rarely fail, but overtightening them causing damage to the piezo quartz is the most common reason why they do.

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Sun 30 Jan 2011 22:14
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - unthrottled
I'm curious as to how one would know that the knock sensor had failed...
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Sun 27 Feb 2011 20:33
Ford Fiesta 1.25 16v 2006MY - Changing knock sensor - 547HEW

Just an update on vehicle. Was in for service this weekend and code check showed no knock sensor DTC's , so as its been dry for a while, we are now sure that it was a moisture ingress issue, possibly via the pcm connector.

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