Faulty Signal

Faulty signal

Checking the diagnostic trouble codes (DTCs)
Check if there are diagnostic trouble codes stored for fuel pressure sensor or ambient pressure sensor, in that case troubleshoot and fix these first.

Do you want to continue with this procedure?

Yes - Checking the fuel pressure sensor

No - ANOTHER TEST

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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). This method assumes that the manometer for measuring fuel pressure is correctly calibrated.

- To connect the manometer, see Fuel pressure gauge Fuel Pressure Gauge
- 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, the circuit for the fuel pressure sensor is defective.









Are the values equal?

Yes - Checking components

No - Checking components and wiring

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Checking components
Check that the fuel level in the tank is not too low (almost no fuel).
Check the connectors between the pump control module and the fuel pump (FP). Check for contact resistance and oxidation.
Check the fuel lines and fuel filter for blockage and leaks.
Remedy as necessary.
Try a new fuel pump (FP) if no fault is found during the above fault-tracing.

Hint: The diagnostic trouble code (DTC) can also be caused by a defective pump control module.

Other information:
- Checking wiring and terminals Checking Wiring And Terminals
- To access or replace the fuel pump (FP), see
- To access or replace the pump control module see Control module fuel pump (FP), replacing, B5244T5, B5254T2 Service and Repair.






Continue - Verification

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Checking components 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:
- Checking wiring and terminals Checking Wiring And Terminals
- To connect the breakout box, see Connecting the breakout box, B5244T5, B5254T2 Connecting the Breakout Box
- For information about signals, see Signal specification Signal Description / Specification
- To access or replace the fuel pressure sensor, see Fuel pressure sensor, replacement, B5244T5, B5254T2 Service and Repair.






Continue - Verification

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Verification




Verification

Verification

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




- Reinstall the connectors, components etc.
- Start the engine and run it to normal operating temperature
- Read off the fuel pump (FP) load.
Check that the engine starts and that the signal is approximately 35% (±5%) when the engine is idling at operating temperature.









Is the function correct?

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 - FAULT-TRACING FAILED

No - Attempt New Test

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FAULT-TRACING FAILED - No Fault Found

Attempt New Test - Checking the diagnostic trouble codes (DTCs)

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