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.
P1405 is set when CPF is in generation mode to get rid of piled P.M but generation has not completed for exceeding designated time (600sec.) or temperature difference between VGT-CPF sensors signal is over set temperature (40℃) during cold condition. This DTC will be set by foreign materials in the CPF, Malfunctioning of DPS signal, Faulty EGTS - VGT or CPF or circuit malfunction.
Item | Detecting Condition | Possible Cause | ||
DTC Strategy | ● Voltage monitoring | ● Dropped regenerationefficiency ● Clogged CPF ● DPS circuit ● DPS component ● EGTS circuit (VGT,CPF) ● EGTS component (VGT,CPF) | ||
Enable Conditions | ● IG KEY "ON" | |||
ThresholdValue | ● Regenerating duration lasts more than the specified duration - 600sec. ● Temperature difference between VGT-CPF sensors signal is over set temperature (40℃) during cold condition. - 1.0sec. | |||
DiagnosticTime | ● Refer to "Threshold Value" | |||
Fail Safe | Fuel Cut | NO | ● Engine check lamp blinks. | |
EGR Off | NO | |||
Fuel Limit | NO | |||
MIL | BLINK | |||
Data analysis about CPF
Connect scantool to Data Link Connector (DLC).
Warm engine up to normal operating temperature.
Turn "OFF" electrical devices and A/C.
Monitor "DIFFERENTIAL PRESSURE" and "PRESSURE PRE CPF" parameter on the scantool.
Specification : "DIFFERENTIAL PRESSURE" and "PRESSURE PRE CPF" data must not be too high or low.
CPF SERVICE REGENERATION procedure.
Connect scantool to Data Link Connector (DLC).
Warm engine up to normal operating temperature.
Turn the all the electrocity (Head lamp -HIGH, Blower motor - Max speed, Defroster)and air conditioner "ON".
Perform the "CPF SERVICE REGENERATION" procedure with scantool.
Specification : CPF regeneration should be O.K when performing CPF service mode.
Electrical systems consist of a lot of harness and connectors, poor connection of terminals can cause various problems and damge of component.
Perform checking procedure as follows.
Check damage of harness and terminals : Check terminals for contact resistance, corrosion and deformation.
Check connecting condition of ECM and component connector : Check terminal seperation, damage of locking device and connecting condition between terminal and wiring.
Disconnect the pin which requires checking at male connector and insert it to the terminal at female connector or checking connecting condition. ( after checking, reconnect the pin at correct position. )
Is the problem found?
▶ Repair the trouble causing part and go to "Verification of Vehicle Repair".
▶ Go to "Power Circuit Inspection".
IG KEY "OFF", ENGINE "OFF"
Disconnect DPS connector.
IG KEY "ON"
Measure the voltage of DPS connector terminal 1.
Specification : 4.8V~5.1V
Is the measured voltage within the specification?
▶ Go to "Signal Circuit Inspection".
▶ Repair open in power circuit and go to "Verification of Vehicle Repair".
Check signal circuit voltage
IG KEY "OFF", ENGINE "OFF"
Disconnect DPS connector.
IG KEY "ON"
Measure the voltage of DPS connector terminal 2.
Specification : 4.8V~5.1V
Is the measured voltage within the specification?
▶ Go to "Ground Circuit Inspection".
▶ Go to "2. Check open in signal circuit" as follows.
Check open in signal circuit
IG KEY "OFF", ENGINE "OFF"
Disconnect DPS connector and ECM connector.
Check continuity between DPS connector terminal 2 and ECM connector(CUD-K) terminal 36.
Specification : Continuity ( below 1.0Ω )
Is the measured resistance within the specification?
▶ Go to "3. Check short in signal circuit" as follows.
▶ Repair open in DPS signal circuit and go to "Verification of Vehicle Repair".
Check short in signal circuit
IG KEY "OFF", ENGINE "OFF"
Disconnect DPS connector and ECM connector.
IG KEY "ON"
Check continutity between DPS connector terminal 2 and chassis ground. ( Test for short to ground )
Check voltage between DPS connector terminal 2 and chassis ground. ( Test for short to battery )
Specification :
Test for short to ground : Discontinuity (Infinite Ω )
Test for short to battery : Below 0.1 V
Is abnormal voltage detected in the circuit with both connector disconnected?
▶ Repair short to battery in signal circuit and go to "Verification of Vehicle Repair".
▶ Go to "Ground Circuit Inspectiont".
IG KEY "OFF", ENGINE "OFF"
Disconnect DPS connector.
IG KEY "ON"
Measure the voltage of DPS connector terminal 1. [ TEST "A" ]
Measure the voltage between DPS connector terminal 1 and terminal 3. [ TEST "B" ]
( terminal 1 : Check + prove , terminal 3 : Check - prove )
Specification : [TEST "A"] Voltage - [TEST "B"] Voltage = below 200mV
Is the measured voltage within the specification?
▶ Go to "Component Inspection".
▶ When "B" voltage is not detected : Repair open in ground circuit and go to "Verification of Vehicle Repair".
▶ When the voltage difference between "A" and "B" is above 200mV : Eliminate the causes of excessive resistance and go to "Verification of Vehicle Repair".
DPS visual inspection
IG KEY "OFF", ENGINE "OFF"
Disconnect DPS connector.
Check DPS terminals for corrosion and contamination.
Check (1)connecting condition of DPS and pressure sensing hose, (2)exhaust gas pressure leakate, (3)miss connection of pressure sensing hose (reverse connection) is detected.
Is DPS related problem detected?
▶ If needed, replace DPS or pressure sensing hose and go to "Verification of Vehicle Repair".
▶ Go to "2. Monitor DPS signal waveform" as follows.
Monitor DPS signal waveform
IG KEY "ON", ENGINE "OFF"
Connect DPS connector.
Connect oscilloscope to DPS connector terminal 2.
After warming engine up, monitor the waveform at idle and during acceleration.
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.
Is DPS signal waveform is similar to the waveform of "Signal Waveform ＆ Data"?
▶ Go to "3. CPF component visual inspection" as follows.
▶ Replace DPS and go to "Verification of Vehicle Repair".
CPF component visual inspection
IG KEY "OFF", ENGINE "OFF"
Visually inspect any evidence of exhaust gas leakage on the connection of the exhaust pipe.
After removing CPF assembly, check any Inside of CPF is contaminated or Catalyst converter is damaged, disengaged or melted.
Specification : Catalyst Converter and PM filter in the CPF should be normal.
Is CPF related problem detected?
▶ Replace CPF and go to "Verification of Vehicle Repair".
▶ Go to "Verification of Vehicle Repair".
※ After replacing CPF, perform the "CPF CHANGE" procedure to reset the ECM with scantool.
After a repair, it is essential to verify that the fault is corrected.
After connecting Scantool select "DIAGNOSTIC TROUBLE CODES(DTCs)" mode.
Clear recorded DTC using Scantool.
Drive the vehicle within DTC "Enable conditions" in "General information".
After selecting "DIAGNOSTIC TROUBLE CODES(DTCs)" mode and check if DTC is recorded again.
Are any DTCs recorded ?
▶ Go to the DTC guide of recorded NO. in Scantool.
▶ System operates within specification.
