ECD SYSTEM, Diagnostic DTC:P1425, P1427, P1428

DTC Code DTC Name
P1425 Differential Pressure Sensor Circuit
P1427 Differential Pressure Sensor Circuit Low
P1428 Differential Pressure Sensor Circuit High

DESCRIPTION

A01CIG8E01

The two sensing chambers of the differential pressure sensor assembly are mounted to monitor the pressure before the DPF (*2) catalytic converter and atmospheric pressure. The sensor itself is not located on the engine assembly in order to reduce the influence of vibration. The sensor is a semiconductor-type that is not influenced by exhaust gases.

The ECM compares the exhaust gas pressure before the DPF catalytic converter and atmospheric pressure by monitoring the pressure using the upstream and downstream sensing chambers of the differential pressure sensor assembly. If the difference between the pressure before and after the catalytic converter exceeds a predetermined level, the ECM judges that the catalytic converter has clogged with particulate matter (PM). When the ECM judges that a partially clogged condition exists, the ECM begins to perform DPF catalyst regeneration.

When the output voltage of the sensor deviates from the normal operating range, the ECM interprets this as a malfunction of the sensor circuit, and DTC P1425, P1427, or P1428 will be set and the MIL will be illuminated.

*2: Diesel Particulate Filter

Tech Tips

If the vacuum hoses of the differential pressure sensor are incorrectly connected (crossed), the ECM interprets this as abnormal pressure difference, and DTC P1426 (Differential pressure sensor installation error) will be set and the MIL will be illuminated.

DTC No. DTC Detection Condition Trouble Area
P1425 Differential pressure sensor assembly output voltage is less than 0.4 V, or more than 4.8 V for 1 second or more (1 trip detection logic)

  • Open or short in differential pressure sensor assembly circuit

  • Incorrect differential pressure sensor assembly hose routing

  • Differential pressure sensor assembly

  • ECM
P1427 Differential pressure sensor output voltage is less than 0.4 V for 1 second or more (1 trip detection logic)

  • Open or short in differential pressure sensor assembly circuit

  • Incorrect differential pressure sensor assembly hose routing

  • Differential pressure sensor assembly

  • ECM
P1428 Differential pressure sensor output voltage is more than 4.8 V for 1 second or more (1 trip detection logic)

  • Open or short in differential pressure sensor assembly circuit

  • Incorrect differential pressure sensor assembly hose routing

  • Differential pressure sensor assembly

  • ECM

Tech Tips


  • DTC P1426 (Differential pressure sensor installation error) will be present if there is incorrect vacuum hose routing to the differential pressure sensor assembly.

  • After confirming DTC P1425, P1427 and P1428, check the differential pressure by selecting the following menus on the tester: Powertrain / Engine and ECT / Data List / DPF Differential Pressure.

    Result
    Condition Differential Pressure Output Sensor Condition
    Ignition switch ON Approximately 0 kPa Normal
    Always -5 kPa or 100 kPa Open or short circuit
    3000 rpm (No engine load) Negative output Incorrect arrangement of hose piping

WIRING DIAGRAM

A01CIXCE01

INSPECTION PROCEDURE

PROCEDURE


  1. READ VALUE USING INTELLIGENT TESTER (DIFFERENTIAL PRESSURE)


    1. Replace the normal DLC3 cable (12 V specification) for the intelligent tester with the 24 V DLC3 cable.

      Note

      Be sure to use the 24 V DLC3 cable when connecting the intelligent tester to the DLC3. Using the normal DLC3 cable (12 V specification) will cause damage to the tester.

    2. Connect the intelligent tester to the DLC3.

    3. Turn the ignition switch to ON.

    4. Turn the tester on.

    5. Enter the following menus: Powertrain / Engine and ECT / Data List / DPF Differential Pressure.

    6. Check that differential pressure is within the specification below.

      Result
      Condition Differential Pressure Proceed to
      Always -5 kPa or less A
      -1 to 1 kPa B
      100 kPa C

    B

    CHECK FOR INTERMITTENT PROBLEMS Click here

    C

    CHECK BLOCKAGE OF VACUUM HOSE AND CATALYST CONVERTER Click here

    A

  2. CHECK CONNECTION OF VACUUM HOSE (DIFFERENTIAL PRESSURE SENSOR ASSEMBLY - CATALYST CONVERTER)


    1. Check if the vacuum hose routing between the differential pressure sensor assembly and the catalyst converter is correct.

    2. Check that there is no exhaust gas leakage between the differential pressure sensor assembly and the catalyst converter.


    NG

    RECONNECT VACUUM HOSE

    OK

  3. CHECK BLOCKAGE OF VACUUM HOSE AND CATALYST CONVERTER

    CAUTION:

    Be careful of being burned by exhaust gases during the following inspection.


    1. Disconnect the vacuum hoses (both upstream and downstream) on the differential pressure sensor assembly.

    2. Start the engine.

    3. Check if there are exhaust gas pulsations from both vacuum hoses during idling.


    NG

    REPLACE CLOGGED PARTS

    OK

  4. CHECK HARNESS AND CONNECTOR (DIFFERENTIAL PRESSURE SENSOR ASSEMBLY - ECM)


    1. Disconnect the differential pressure sensor assembly connector.

    2. Disconnect the ECM connectors.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance (Check for Open)
      Tester Connection Condition Specified Condition
      E23-27 (PEX) - D19-2 (VP) Always Below 1 Ω
      E22-18 (VC) - D19-3 (VC) Always Below 1 Ω
      E22-28 (E2) - D19-1 (GND) Always Below 1 Ω
      Standard Resistance (Check for Short)
      Tester Connection Condition Specified Condition
      E23-27 (PEX) or D19-2 (VP) - Body ground Always 10 kΩ or higher
      E22-18 (VC) or D19-3 (VC) - Body ground Always 10 kΩ or higher

    4. Reconnect the differential pressure sensor assembly connector.

    5. Reconnect the ECM connectors.


    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR (DIFFERENTIAL PRESSURE SENSOR ASSEMBLY - ECM)

    OK

    REPLACE DIFFERENTIAL PRESSURE SENSOR ASSEMBLY Click here