P0193 – Rail Pressure Sensor Circuit High Input MMC L200 IV

admin September 28, 2020

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. 70) and earthed to the engine-ECU (terminal No. 88) from the rail pressure sensor (terminal No. 3).

The sensor signal is inputted to the engine-ECU (terminal No. 64) 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

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.

The rail pressure sensor output voltage is 4.85 V or more for 0.5 second.

PROBABLE CAUSES

Failed rail pressure sensor

Open circuit in rail pressure sensor circuit or loose connector contact

Failed engine-ECU

DIAGNOSIS PROCEDURE

STEP 1. M.U.T.-III data list

Item 63: Rail pressure sensor

Q. Is the check result normal?

STEP 2. Connector check: A-44 rail pressure sensor connector

Q. Is the check result normal?

STEP 3. Perform resistance measurement at A-44 rail pressure sensor connector.

Disconnect connector, and measure at harness side.

Resistance between terminal No. 3 and earth.

Q. Is the check result normal?

STEP 4. Connector check: C-105 engine-ECU connector

Q. Is the check result normal?

STEP 5. Check harness between A-44 (terminal No. 3) rail pressure sensor connector and C-105 (terminal No. 88) engine-ECU connector.

Check earthing line for open circuit.

Q. Is the check result normal?

STEP 6. M.U.T.-III data list

Item 63: Rail pressure sensor

Q. Is the check result normal?

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

Item 63: Rail pressure sensor

Q. Is the check result normal?

Author: admin