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 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 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. Perform resistance measurement at exhaust differential pressure sensor connector.

Disconnect connector, and measure at harness side.
Ignition switch: ON
Resistance between terminal engine-ECU DDPE line and body earth.

OK: Continuity (2 Ω or less)

Q. Is the check result normal?

	Go to Step 5.

	Go to Step 3.

STEP 3. Check harness between exhaust differential pressure sensor connector terminal and engine-ECU connector terminal DDPE.

Check earthing line for open circuit and damage.

Q. Is the check result normal?

	Go to Step 4.

	Repair or replace the connector, or repair the damaged harness wire.

STEP 4. 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 5. 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 4.

	Check end.