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 .

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: A-75 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 A-75 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-39 engine-ECU connector

Q. Is the check result normal?

	Go to Step 5 .

	Repair or replace the connector.

STEP 5. Check harness between A-75 (terminal No. 3) exhaust differential pressure sensor connector and B-39 (terminal No. 80) engine-ECU connector.

note

Before checking harness, check intermediate connector A-10, and repair if necessary.

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 .

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?

	Go to Step 6 .

	Check end.

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