Code No. P0193: Rail Pressure Sensor Circuit High Input

OPERATION

A power voltage of 5 V is applied to the rail pressure sensor power terminal (terminal No. 1) from the engine-ECU (terminal No. 81) and earthed to the engine-ECU (terminal No. 76) from the rail pressure sensor (terminal No. 3).
The sensor signal is inputted to the engine-ECU (terminal No. 56) from the rail pressure sensor output terminal (terminal No. 2).

FUNCTION

The rail pressure sensor converts the rail pressure into a voltage signal and inputs the signal to the engine-ECU.
In response to the signal, the engine-ECU corrects the fuel injection quantity.

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 rail pressure sensor output voltage is 4.85 V or more.

PROBABLE CAUSES

Failed rail pressure sensor
Open circuit in rail 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 63: Rail 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-124 rail 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-124 rail pressure sensor connector.

Disconnect 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: D-213 engine-ECU connector

Q. Is the check result normal?

	Go to Step 5.

	Repair or replace the connector.

STEP 5. Check harness between B-124 (terminal No. 3) rail pressure sensor connector and D-213 (terminal No. 76) engine-ECU connector.

note

Before checking harness, check intermediate connector B-127, and repair if necessary.

Check earthing line for open circuit.

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 63: Rail 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. When the engine-ECU is replaced, write the chassis number (Refer to GROUP 00 - Precautions Before Service - How to Perform Chassis Number Writing ). After replacing the engine-ECU, register the injector identification code and learn fuel injection (Refer to GROUP 00 - Precautions Before Service - What The Common Rail Engine Learns ).

STEP 7. M.U.T.-III data list

Refer to Data List Reference Table .

Item 63: Rail 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 common rail assembly.