Injector wiring loom breakdown is one of the more common faults that the diesel engine suffers with, fortunately its a cheap enough repair with the loom costing around Ã,£60 from VW and carrying part number 038 971 600. Common faults with the loom can range from misfires to juddering to starting problems.

The process of replacement is fairly strait forward but quite time consuming as the loom is buried away within the cylinder head and requires separation to remove it.

First thing to do is remove the plastic engine over-cover by pulling it up and forward. The foam pad can now be removed (assuming its fitted!) and then you'll be able to see the top of the engine. The following photo shows the approximate location of the loom:

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Next, we need to remove the 13 bolts that clamp the rocker cover to the cylinder head - start by cracking the tension of each one and then remove them. Disconnect the breather hose from the rear left.

Separation of the rocker cover can now occur, use a large flat blade to apply gentle pressure if it won't easily free.

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With the rocker cover removed we can now see the loom running along the front of the head. Each injector has one connector which pulls up to disconnect, if needed you can use a levering tool to separate it but it shouldn't be too tight. Once disconnected, slide it into the holder (green arrow) to allow easier removal of the loom: (The final picture shows the loom as it comes, with the connectors in the holders)

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Disconnect (by unscrewing) the connector on the outside of the head and then remove the two bolts that hold it in place (It will be necessary to remove the engine cover mounting bracket first - one bolt). You'll then be able to withdraw the entire loom out from the right side of the engine taking care to depress the spring clip holders as it slides out.

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Installing the new loom is a reverse of the above, taking care to tighten the cover back up in a star patten to avoid undue tension

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