Code No. P0192: Rail Pressure Sensor Circuit Low Input
OPERATION
- A power voltage of 5 V is applied to the rail pressure sensor power terminal from the engine-ECU connector terminal FPS5 and earthed to the engine-ECU connector terminal FPSE from the rail pressure sensor connector terminal.
- The sensor signal is inputted to the engine-ECU connector terminal FPS from the rail pressure sensor output terminal.
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 JUDGEMENT
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.
Judgement Criterion
- The rail pressure sensor output voltage is 0.70 V or less.
FAIL-SAFE AND BACKUP FUNCTION
- The rail pressure is controlled in the range between 50 and 100 MPa.
- The fuel injection amount is restricted (output restriction).
- The open angle of the accelerator pedal is restricted.
- The throttle valve is closed (fixed opening degree).
- The EGR control is stopped (fully closed).
- The DPF regeneration is prohibited.
PROBABLE CAUSES
- Failed rail pressure sensor
- Open/short circuit or harness damage in rail pressure sensor circuit or loose connector contact
- Failed engine-ECU
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STEP 1. M.U.T.-III data list
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- Refer to Data List Reference Table
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- Item 63: Rail pressure sensor
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Q.
Is the check result normal?
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 Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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 Go to Step 2.
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STEP 2. Resistance measurement at fuel pressure sensor connector (FPS line).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Measure the resistance between the fuel pressure sensor connector (FPS line) and body earth.
OK: No continuity
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Q.
Is the check result normal?
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Go to Step 4.
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Go to Step 3.
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STEP 3. Check of short to earth in FPS line between rail pressure sensor connector and engine-ECU connector.
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Q.
Is the check result normal?
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Go to Step 5.
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Repair the connector(s) or wiring harness.
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STEP 4. Voltage measurement at rail pressure sensor connector (FPS line).
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(1)Disconnect connector, and measure at sensor side.
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(2)With the special tool test harness (MB991658) bridge only the mating terminals of FPS5 line and FPSE line of the disconnected connector.
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(4)Check the voltage between the rail pressure sensor connector (FPS line) and body earth.
OK: 0.85 V or more
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Q.
Is the check result normal?
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Go to Step 5.
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Replace the rail pressure sensor.
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STEP 5. M.U.T.-III data list
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- Refer to Data List Reference Table .
- Item 63: Rail pressure sensor
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Use Troubleshooting/Inspection Service Points - How to Cope with Intermittent Malfunctions).
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Replace the engine-ECU.
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