A 2012 Ford Mondeo 2.0 TDCI recently entered our workshop with an engine malfunction warning lamp illuminated. After an initial diagnostic check we retrieved an error code: P244C this relates to DPF bank 1 - Exhaust temperature too low for regeneration, and after reading the soot accumulation figure within the DPF (which was excessive) it indicated that regeneration was not being enabled.
To enable regeneration the DPF temperature must be raised significantly (approx. 600°C) to achieve this manufacturers employ a number of methods. This particular system utilizes a fuel vaporizer (see photo). This device is located in the exhaust system upstream of the DPF. Its function is to inject diesel directly into the DPF when requested to raise the temperature and enable regeneration.
The faults apparent on this vehicle suggested a fault with this component so we began our investigation at this point. We disconnected the fuel and electrical supplies and removed the vaporizer. Once removed we prompted the vaporizer pump to operate using the function on the Autologic device, the pump is operated by method of PWM (Pulse Width Modulation) this test was successful and we established fuel delivery to the vaporizer.
Next we checked the discharge orifice for obstruction and the integrity of the unit heating circuit, both found to be ok.
We connected our Mityvac to the fuel line on the vaporizer, at this point we discovered a restriction between the inlet pipe and discharge nozzle indicating a defective vaporizer. Finally a new vaporizer was installed, primed and a forced regeneration performed. An extended road test was carried out resulting in no apparent faults.