2007 Polo 1.2 S - Camshaft Position Sensor (G40): Signal Low (16726) HELP

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PHIXER
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Posts: 5
Joined: Mon Jun 12, 2017 11:55 am
Drives: 2007 MK IV 1.2 S
Location: Hertfordshire

2007 Polo 1.2 S - Camshaft Position Sensor (G40): Signal Low (16726) HELP

Post by PHIXER »

Hi All,

I wonder if you can lend a advice after lengthy diagnostics trying to find the issue to a Camshaft Position Sensor (G40): Signal Low issue.

This started a few months ago where I first gave the sensor a clean which momentarily shut off the MIL light with a reader & erasure of codes. I then replaced the spark plugs a few months back and found the problem remained but was intermittent as before. As time progressed and scratching my head my yearly service came & tells me I need to replace my spark plugs and coils with the coils having been replaced only 2 years ago (Bosch); this recommendation was made without running diagnostics with a reader.

So having looked in to this already I decided to re-investigate. I took a look at the coils which look fine bar cylinder 1 which had some brown marking to the end presumably a scorch mark. I then examined the spark plugs which showed a light covering of carbon on them, however, the cylinder 1 plug looked different to the others. I had darker deposits on it and a bit of oil (fouling) so I assume this is the problem.

However, despite me possibly having a defective spark plug I don't feel this will solve the Camshaft Position Sensor (G40): Signal Low issue as this pre-existed the new spark plug replacement unless I replaced bad plugs with a dodgy batch.

Vehicle has done 120K so this leaves either replacing the ignition coils again with plugs, timing chain or potentially more serious issue. :banghead::banghead:

Any thought most appreciated.
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