Fault-Tracing Information

Fault-tracing

Checking the fuel pressure sensor

Note! If diagnostic trouble codes (DTC) for the fuel pressure sensor or atmospheric pressure sensor are stored, these diagnostic trouble codes (DTC) must be fault-traced and remedied first.

Hint: The method below is used to check whether the diagnostic trouble code (DTC) was caused by a faulty fuel pressure sensor. This can be done by comparing the fuel pressure sensor signal (displayed in VIDA) with the actual fuel pressure (displayed on a manometer connected to the wiring for the fuel injection system).

- Connect the pressure gauge: Fuel pressure gauge Fuel Pressure Gauge

Caution! The pressure in the fuel injection system can reach approximately 650 kPa when this diagnostic trouble code (DTC) is stored. Use an adapted manometer.

- Run the engine to operating temperature. Allow the engine to idle.
- Air conditioning (A/C) off.
Read off the relative fuel pressure.
The relative fuel pressure is calculated from the fuel pressure sensor and the atmospheric pressure sensor signal (= absolute pressure minus atmospheric pressure).
Check that the value on the manometer and the value displayed in VIDA are roughly the same. If the values are different, the circuit for the fuel pressure sensor is defective.

Is the fuel pressure sensor correct?

Yes - Checking components

No - Checking the component and wiring

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Checking components
Check the connectors between the fuel pump (FP) control module and the fuel pump (FP). Check for contact resistance. Check for oxidation.
Remedy as necessary.
Try a new fuel pump (FP) control module if no fault is found during the above fault-tracing.

Other information
- Fuel pump driver module, B5254T5, TF-80SC Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals. Permanent Faults

Continue - Verification

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Checking the component and wiring
Check the fuel pressure sensor connectors. Check for contact resistance and oxidation.
Remedy as necessary.
Try a new fuel pressure sensor if no fault is found during the above fault-tracing.

Other information
- Connecting the breakout box, B5254T5 Connecting the Breakout Box, Engine Control Module (ECM)
- Signal specification, B5254T5 Signal Specification, Engine Control Module (ECM)
- Pressure sensor, fuel rail (FRP), B5254T5 Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals. Permanent Faults

Continue - Verification

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Verification

Verification

Hint: After carrying out the repair, check that the fault has been remedied.

- Connect a manometer.
- Run the engine to operating temperature. Allow the engine to idle.
- Air conditioning (A/C) off.
Read off the relative fuel pressure.
The relative fuel pressure is calculated from the fuel pressure sensor and the atmospheric pressure sensor signal (= absolute pressure minus atmospheric pressure).
Check that the value on the manometer and the value displayed in VIDA are the same. If the values are different, this indicates incorrect function.

- Ignition off.
- Reinstall the connectors, components etc.
- Engine idling.
- Read off the fuel pressure and the fuel pump (FP) work load.
- The upper digital display shows the absolute fuel pressure, read from the fuel pressure sensor.
- The middle digital display shows the fuel pump's current work load to maintain current fuel pressure (normal value 50% ±10%).
- The lower digital display shows the relative fuel pressure, calculated from the fuel pressure sensor and the atmospheric pressure sensor (=absolute pressure minus atmospheric pressure). If a pressure gauge is connected during the test, it must indicate this pressure.
Check the fuel pressure value together with the value for the fuel pump (FP) work load. Requested pressure is 400 kPa at idle. Absolute fuel pressure lower than 400 kPa, together with high work load on the fuel pump, indicates malfunction in the pressure control.

Hint: At start of the vehicle, a higher pressure is requested at first, 500 kPa, which then drops to 400 kPa after approx. half a minute.

Is the function OK?

Yes - VERIFIED

No - VERIFICATION FAILED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED - Fault-tracing information

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Fault-tracing information

Information

Fault-tracing information
The fault should have been detected and remedied. As this is not the case fault-tracing has failed.
Exit fault-tracing for this diagnostic trouble code (DTC) or make another attempt.

Do you want to exit fault-tracing?

Yes - Exit fault-tracing

No - Attempt New Test

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Attempt New Test - Checking the fuel pressure sensor

FAULT-TRACING FAILED - No Fault Found

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