Code No. P2454: Exhaust Differential Pressure Sensor Circuit Low Input


OPERATION



  • A power voltage of 5 V is applied to the exhaust differential pressure sensor power terminal from the engine-ECU connector terminal DDP5 and earthed to the engine-ECU connector terminal DDPE from the exhaust differential pressure sensor connector terminal.
  • The sensor signal is inputted to the engine-ECU connector terminal DDPS from the exhaust differential pressure sensor output terminal.

FUNCTION



  • The exhaust differential pressure sensor outputs the voltage to the engine-ECU in accordance with the difference in the voltage between the DPF upstream area and the DPF downstream area.
  • The engine-ECU anticipates the amount of PM accumulated in the DPF through this output voltage.

TROUBLE JUDGMENT


Check Conditions
  • Battery positive voltage is 8 - 16 V
  • 2 seconds later after the ignition switch has been in "ON" position or the engine has started up
Judgment Criterion
  • The exhaust differential pressure sensor output voltage is 0.49 V or less.

FAIL-SAFE AND BACKUP FUNCTION



  • The throttle valve is opened (Electrical discontinuity).
  • The EGR control is stopped (fully closed).
  • The DPF regeneration is prohibited.
  • The AS&G control is prohibited.

PROBABLE CAUSES



  • Failed exhaust differential pressure sensor
  • Open/short circuit or harness damage in exhaust differential pressure sensor circuit or loose connector contact
  • Failed engine-ECU

DIAGNOSTIC PROCEDURE

STEP 1. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 120: Exhaust differential pressure sensor

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Go to Step 2.

STEP 2. Perform voltage measurement at exhaust differential pressure sensor connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal engine-ECU DDP5 line and body earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?
Go to Step 6.
Go to Step 3.

STEP 3. Perform voltage measurement at engine-ECU connector.

  • Disconnect engine-ECU harness, and connect special tool power plant ECU check harness (MB992291) to measure at connector for inspection.
  • Ignition switch: ON
  • Voltage between terminal DDP5 and body earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?

    Repair or replace the connector, or check and repair harness between exhaust differential pressure sensor connector terminal and engine-ECU connector terminal DDP5.

    • Check power supply line for open circuit.
Go to Step 4.

STEP 4. Check harness between exhaust differential pressure sensor connector terminal and engine-ECU connector terminal DDP5.

  • Check power supply line for short circuit.

Q. Is the check result normal?
Go to Step 5.
Repair or replace the connector, or repair the damaged harness wire.

STEP 5. M.U.T.-III data list

  • Refer to Data List Reference Table .

  1. Item 120: Exhaust differential pressure sensor

Q. Is the check result normal?
Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions ).
Replace the engine-ECU.

STEP 6. Check harness between exhaust differential pressure sensor connector terminal and engine-ECU connector terminal DDP5.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 7.
Repair or replace the connector, or repair the damaged harness wire.

STEP 7. Check harness between exhaust differential pressure sensor connector terminal and engine-ECU connector terminal DDPS.

  • Check output line for open/short circuit and damage.

Q. Is the check result normal?
Go to Step 8.
Repair or replace the connector, or repair the damaged harness wire.

STEP 8. Replace the exhaust differential pressure sensor

  • After replacing the exhaust differential pressure sensor, carry out the forcible DPF regeneration. (Refer to GROUP 17 - Emission Control <DIESEL> - Diesel Particulate Filter (DPF) System - Forcible DPF Regeneration ). After carrying out the forcible DPF regeneration, reconfirm diagnosis code.

Q. Is the diagnosis code set?
Go to Step 5.
Check end.