If something is blocking the particulate (aka FAP) filter in your Peugeot 307 with an Hdi common rail engine, your car will usually notify you with a flashing Particle Filter warning lamp. If this happens, you should use the Scan Tool to enter the engine control unit (ECU) diagnostic. This should display more specific information about any problems with your filter. Read the fault codes and take measures specific to those codes to clear the errors.
A Fault Code Will Read: "Filter Blocked" or "Filter Clogged"
When "Filter Blocked" fault codes show up, your FAP filter has either reached the end of its service life or it is dirty. In either case, you or your technician should perform a Regeneration to burn off any remaining particles on the filter. If the warning still comes on after the regeneration, replace the filter. Regenerating a Peugeot 307 involves bringing the temperature inside the filter to around 450 degrees C. Under normal driving conditions, this condition will result after 250 to 300 miles, but stop-and-start urban driving may not be conducive to this. Instead, your technician could force a regeneration under specified temperature conditions and fuel tank levels.
A Fault Code May Also Read: "Minimum Level"
In addition to any codes alerting to you to a blocked FAP filter itself, other codes may refer to the other component of the FAP system in the Peugeot 307, or the additive that assists the diesel in reaching the necessary temperature to burn off the trapped particles. This additive is stored in its own designated chamber. If the additive is low, you must refill or top off the reservoir. The error code will inform you of this with a "Minimum Level" indicator. After refilling the reservoir, you or your technician must reset the Quantity of Additive function to zero and reprogram the value. You will find that this fault code sometimes shows up simultaneously with the Filter Blocked code, in which case you should both replace the filter and replenish the additive.
Reduced Power and Fuel Economy
The function of the FAP filter is to reduce diesel particulate levels in engine emissions by filtering the exhaust. When the FAP filter becomes blocked, it can't do its job of filtering the trapped particles. This may or may not result in a noticeable change in the car's performance. However, you may see reduced power, sluggishness and reduced fuel economy.
Fuel Level Sensor May Be Faulty
If you replaced the FAP filter, refilled the additive and reset the counters, and the "Filter Blocked" warning still returns, you may have the concurrent problem of a Fuel Level sensor going out. This is the sensor that monitors the fuel level, allowing the proportional amount of additive to be injected. Malfunction of the sensor could prevent operation, requiring you to replace the sensor; if you are still under warranty, Peugeot should cover this cost.