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 (terminal No. 1) from the engine-ECU (terminal No. 94) and earthed to the engine-ECU (terminal No. 80) from the exhaust differential pressure sensor (terminal No. 3).
  • The sensor signal is inputted to the engine-ECU (terminal No. 56) from the exhaust differential pressure sensor output terminal (terminal No. 2).

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. Connector check: B-118 exhaust differential pressure sensor connector

Q. Is the check result normal?
Go to Step 3 .
Repair or replace the connector.

STEP 3. Perform voltage measurement at B-118 exhaust differential pressure sensor connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Voltage between terminal No. 1 and earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?
Go to Step 9 .
Go to Step 4 .

STEP 4. Perform voltage measurement at B-09 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 No. 94 and earth.
OK: 4.9 - 5.1 V

Q. Is the check result normal?
Go to Step 8 .
Go to Step 5 .

STEP 5. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?
Go to Step 6 .
Repair or replace the connector.

STEP 6. Check harness between B-118 (terminal No. 1) exhaust differential pressure sensor connector and B-09 (terminal No. 94) engine-ECU connector.

  • Check power supply line for short circuit.

Q. Is the check result normal?
Go to Step 7 .
Repair the damaged harness wire.

STEP 7. 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 8. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?

    Check and repair harness between B-118 (terminal No. 1) exhaust differential pressure sensor connector and B-09 (terminal No. 94) engine-ECU connector.

    • Check power supply line for open circuit.
Repair or replace the connector.

STEP 9. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?
Go to Step 10 .
Repair or replace the connector.

STEP 10. Check harness between B-118 (terminal No. 1) exhaust differential pressure sensor connector and B-09 (terminal No. 94) engine-ECU connector.

  • Check power supply line for damage.

Q. Is the check result normal?
Go to Step 11 .
Repair the damaged harness wire.

STEP 11. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?
Go to Step 12 .
Repair or replace the connector.

STEP 12. Check harness between B-118 (terminal No. 2) exhaust differential pressure sensor connector and B-09 (terminal No. 56) engine-ECU connector.

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

Q. Is the check result normal?
Go to Step 13 .
Repair the damaged harness wire.

STEP 13. 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, re-check the trouble symptoms.

Q. Is the check result normal?
Check end.
Go to Step 7 .