P2458: extended regeneration time is different from a measured soot limit

P2458 concerns diesel particulate-filter regeneration duration. Audi's CPNB chart lists a regeneration time greater than 3,600 seconds, equivalent to one hour. That is a time criterion; the row does not assign a soot mass or prove how restricted the filter is.

Duration does not identify the reason

As diagnostic interpretation, a long regeneration event needs an explanation rather than an automatic decision to replace the DPF. The quick-reference row does not tell whether the underlying issue involves the filter, the conditions required for regeneration or information used by the controller. Those causes need the actual diagnostic procedure.

The threshold is also not an instruction to keep a vehicle regenerating for an hour. It describes a fault boundary in this calibration, not a prescribed service operation or a guarantee that regeneration is safe under the vehicle's present conditions.

Preserve the event evidence

A useful diagnostic record distinguishes reported regeneration duration from independently assessed loading and other engine faults. The source supplies no universal forced-regeneration method or maximum permitted filter load here. This monitor explanation is limited to the CPNB section of Audi's 2014 A6/S6 reference book and does not turn a duration fault into an unsupported ash or soot diagnosis.

Source: Audi 2014 A6/S6 Quick Reference Specification Book.