Code No. P2455: Exhaust Differential Pressure Sensor Circuit High 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 down stream 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 4.79 V or more.

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 circuit 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 resistance measurement at B-118 exhaust differential pressure sensor connector.

  • Disconnect connector, and measure at harness side.
  • Ignition switch: ON
  • Resistance between terminal No. 3 and earth.
OK: Continuity (2 Ω or less)

Q. Is the check result normal?
Go to Step 7 .
Go to Step 4 .

STEP 4. Connector check: B-09 engine-ECU connector

Q. Is the check result normal?
Go to Step 5 .
Repair or replace the connector.

STEP 5. Check harness between B-118 (terminal No. 3) exhaust differential pressure sensor connector and B-09 (terminal No. 80) engine-ECU connector.

  • Check earthing line for open circuit and damage.

Q. Is the check result normal?
Go to Step 6 .
Repair the damaged harness wire.

STEP 6. 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 7. 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 6 .