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
P0473 is set when the voltage above 4.72V - maximum output voltage of DPS - is detected for more than 0.6 sec.. or measured Differential pressure is above 500 hPa - the upper limiting value - for more than 1 sec.
This code is due to 1) short beween power and signal circuit or 2) short to battery in signal circuit or 3) short to ground in ground circuit.
DTC Detecting Condition
Item | Detecting Condition | Possible Cause |
DTC Strategy | ? Voltage monitoring | ? DPS Wiring ? DPS component ? Reversly connected DPS hose line ? Clogged DPS ? Clogged CPF inlet section ? Clogged CPF |
Enable Conditions | ? IG KEY "ON" |
Threshold Value | ? Short to battery in signal circuit ? Short between power and signal circuit ? Open in signal circuit ? Open in ground circuit |
Diagnostic Time | ? Refer to DTC description. |
Fail Safe | Fuel Cut | NO | ? Engine check lamp blinks. ? Differential pressure considered as 10hPa. ? Soot simulation ON mode activated ? Regeneration mileage shorten |
EGR Off | NO |
Fuel Limit | NO |
Check Lamp | YES |
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.