Fault-Tracing Information
Fault-tracing
Checking 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 following method is for checking if the diagnostic trouble code has been caused by a defective fuel pressure sensor. This can be done by comparing the fuel pressure sensor's readout signal with actual fuel pressure (readout on pressure gauge connected to fuel system's lines).
- Connect 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 until it is warm and let it idle.
- A/C off.
Read off relative fuel pressure.
The relative fuel pressure is calculated from the fuel pressure sensor's and the atmospheric pressure sensor's signal (=absolute pressure minus atmospheric pressure).
Check that the value on the pressure gauge and the readout value are about the same. Different values indicate malfunction in the circuit for the fuel pressure sensor.
Is the fuel pressure sensor OK?
Yes - Checking components
No - Checking components and wiring
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Checking components
Check the connectors between fuel pump module and the fuel pump for contact resistance and oxidation.
Try with a new fuel pump module if no malfunction is found in the above troubleshooting.
Remedy as necessary.
Other information
- Fuel pump driver module, B6304T4, TF-80SC AWD Service and Repair
- Checking wiring and terminals Checking Wiring and Terminals. Permanent Faults
Continue - Verification
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Checking components and wiring
Check the fuel pressure sensor's connector for contact resistance and oxidation.
Try with a new fuel pressure sensor if no malfunction is found in the above troubleshooting.
Remedy as necessary.
Other information
- Connecting the breakout box, B6304T4 Breakout Box Connection, Engine Control Module (ECM)
- Signal specification, B6304T4 Signal Specification, Engine Control Module (ECM)
- Checking wiring and terminals Checking Wiring and Terminals. Permanent Faults
Continue - Verification
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Fault-tracing information
Attempt New Test - Checking fuel pressure sensor
FAULT-TRACING FAILED - No Fault Found
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
- Ignition off
- Reinstall the connectors, components etc.
- Engine idling
- Read off the fuel pressure and the work load of the fuel pump.
- The upper digital display and the graphic display (red font color) indicate the absolute fuel pressure, calculated from the fuel pressure sensor
- The center digital display (blue font color) indicates the current work load required for the fuel pump (FP) to maintain the present fuel pressure. (Normal value 50 % ±10& %.)
- The lower digital display indicates the relative fuel pressure (white font color), calculated from the fuel pressure sensor and the atmospheric pressure sensor (= absolute pressure minus atmospheric pressure). If a manometer is connected during the test, it should indicate this pressure.
Check the fuel pressure value together with the value for the fuel pump work load. The requested pressure is 380 kPa at idle speed. A (relative) fuel pressure lower than 380 kPa together with a high fuel pump work load indicates a fault in pressure regulation.
Is the signal within its permitted range?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - FAULT FOUND
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Verification
Verification
Hint: After carrying out the repair, check that the fault has been remedied.
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.
- Connect pressure gauge: Fuel pressure gauge Fuel Pressure Gauge
- Run the engine until it is warm and let it idle.
- A/C off.
Read off relative fuel pressure.
The relative fuel pressure is calculated from the fuel pressure sensor's and the atmospheric pressure sensor's signal (=absolute pressure minus atmospheric pressure).
Check that the value on the pressure gauge and the readout value are the same. Different values indicate malfunction.
Is the function OK?
Yes - VERIFIED
No - VERIFICATION FAILED
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VERIFICATION FAILED - Fault-tracing information
VERIFIED - FAULT FOUND
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