Component Location
General Description
Differential pressure sensor(DPS) is piezzo electric type sensor. Sensing the differential pressure between in front of CPF and in the back of CPF, DPS outputs linear signal from 0~5V. Using output signal, DPS detects the amount of soot, sulfide, SOF(soluble organic fraction) to determine if CPF regeneration is needed.
? CPF regeneration : When vehicle is in steady speed condition and above normal engine loading condition, if differential pressure between before and after CPF is above the specified pressure, ECM considers that stored soot inside of CPF is excessive. In this condition, exhaust gas tempt. is raised by post injection 1 and 2 to warm CPF up to 550?~650?. In this high tempt, soot inside of CPF burns up naturally and this mechanism is called as "CPF regeneration".
Most of soot is burned up during regeneration process but a little amount of soot is not burned up and stored inside of CPF continuously. The stored soot decreases the efficiency of CPF slowly. DPS corrects CPF regeneration period and duration as comparing and calculating the differential pressure due to stored soot with the total distance covered.
DTC Description
P1405 is set when regenerating duration lasts more than 600 sec.. This code is often because normal regeneration was not performed as vehicle had driven in city centre.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | ? Voltage monitoring | ? Dropped regeneration efficiency ? Clogged CPF |
Enable Conditions | ? IG KEY "ON" |
Threshold Value | ? Regenerating duration lasts more than the specified duration |
Diagnostic Time | ? 600 sec. |
Fail Safe | Fuel Cut | NO | ? Engine check lamp blinks. |
EGR Off | NO |
Fuel Limit | NO |
Check Lamp | BLINK |
Specification
Schematic Diagram
Signal Waveform
As accelerating, DPS signal output voltage does not vary too much. Even when accelerator pedal is fully depressed, the signal voltage fluctuates just a little bit like "Fig. 2". However, the more CPF is used, the more waveform fluctuates.