Cause

Failed glow plug control module

The module switching current to a diesel's glow plugs, before and often for a while after starting. It is a high-current device and fails far more often than the plugs themselves, so hard cold starting with white smoke is worth testing here before six plugs are fitted — several of which usually shear on removal.

Typically a moderate job.

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Codes this can cause (31)

Codes where this is a likely explanation first, rather than merely a possible one.

Information, not instruction

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Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.

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