DPF VAPORISERS

Instead of the engine management system providing a series of post-injections which permit diesel to enter the exhaust and combust the soot, various Ford models employ a fuel vaporiser instead, bolted to the exhaust system. A glow-plug is built within the unit to vaporise the fuel, prior to it being injected into the exhaust gas stream ahead of the diesel oxidation catalyst. This raises the DPF temperature sufficiently to combust the soot.

Faults will cause the engine management light to illuminate, which might be accompanied by the vehicle going into ‘limp-home’ mode. Unless a blown fuse, tired fuel pump or glow plug relay is at fault, the vaporiser is the likely cause. Soot can clog the outlet nozzle and is a common issue. Overheating tends to result from insufficient fuel reaching the vaporiser. If the glow plug fails, the fuel will not be vaporised and this causes black smoke to be emitted from the exhaust.

You can test this using a multimeter. Should you measure fewer than 0.8 ohms, or more than 1.3 ohms, the glow plug is no longer serviceable. As the vaporiser can be neither cleaned, nor dismantled, replacement is the only option.

ELTA Automotive told CM that Ford’s Mondeo is particularly prone to fuel vaporiser faults, with the most common fault codes encountered being ‘P246B-00: Vehicle Conditions Incorrect for Diesel Particulate Filter Regeneration’, ‘P2463-00: Diesel Particulate Filter – Soot Accumulation’ and ‘P24A4-00: Diesel Particulate Filter Restriction – Soot Accumulation Too High’.

After the fault has been found, which is likely to include replacing the vaporiser, clear the fault codes and run the vehicle in conditions that induce a DPF regeneration.