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Signal Sporadic: Permanent Fault






Signal sporadic: Permanent fault

EFI-621 Fuel tank pressure sensor, signal

Checking diagnostic trouble codes (DTCs)












- Ignition off.
- Check fuel tank pressure sensor connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Check control module connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Check connector 24/2 and 24/4 for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Fuel tank pressure sensor connected
- Control module connected.
- Start the engine and idle it.
- Wait 5 minutes.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).

If EFI-621 is stored it should have intermittent status.

OK - Fault-tracing information

Not OK - Checking cables and terminals

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Fault-tracing information
- The diagnostic trouble code (DTC) has been caused by poor contact in the fuel tank pressure sensor and/or engine control module (ECM) connectors.

Continue - Verification

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Checking cables and terminals












- Check fuel tank pressure sensor and/or engine control module (ECM) connector for loose connections according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
- Check cable between fuel tank pressure sensor terminal 1 and engine control module (ECM) #B29 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , an intermittent short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , and an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
- Check the cable between atmospheric pressure sensor terminal 3 and engine control module (ECM) #B22 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , an intermittent short-circuit to ground according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults , and an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
- Check cable between fuel tank pressure sensor terminal 2 and engine control module (ECM) #B28 for an intermittent open-circuit according to Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
- The fuel tank pressure sensor power cable is connected inside the engine control module (ECM) to the air conditioning (A/C) pressure sensor, fuel tank pressure sensor and accelerometer power cables.
If anything happens to any of these cables all four will be affected.
Check cables between:
- air conditioning (A/C) pressure sensor terminal 3 and engine control module (ECM) #B29.
- atmospheric pressure sensor terminal 1 and engine control module (ECM) #B15
- accelerometer terminal 1 and engine control module (ECM) #B1
for an intermittent short-circuit to supply voltage according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault and an intermittent short-circuit to ground Checking wiring and terminals. Intermittent faults Checking Wiring and Terminals. Intermittent Faults.
- Reinstall all components.
- Start the engine and idle it.
- Wait 5 minutes.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).

If EFI-621 is stored it should have intermittent status.

OK - Verification

Not OK - Checking the air conditioning (A/C) pressure sensor

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Checking the air conditioning (A/C) pressure sensor








- Ignition off.
- Fuel tank pressure sensor connected
- Disconnect air conditioning (A/C) pressure sensor.

Hint: Diagnostic trouble codes (DTCs) may be stored for the air conditioning (A/C) pressure sensor; erase codes when fault-tracing is completed.

- Start the engine and idle it.
- Wait 5 minutes.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).

If EFI-621 is stored it should have intermittent status.

OK - Replacing component

Not OK - Checking accelerometer

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Replacing component
- Try a new air conditioning (A/C) pressure sensor.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking accelerometer








- Ignition off.
- Fuel tank pressure sensor connected
- Connect air conditioning (A/C) pressure sensor.
- Disconnect accelerometer.

Hint: Diagnostic trouble codes (DTCs) may be stored for the accelerometer; erase codes when fault-tracing is completed.

- Start the engine and idle it.
- Wait 5 minutes.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).

If EFI-621 is stored it should have intermittent status.

OK - Replacing component

Not OK - Checking atmospheric pressure sensor

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Replacing component
- Try a new accelerometer.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Checking atmospheric pressure sensor








- Ignition off.
- Fuel tank pressure sensor connected
- Connect the accelerometer.
- Disconnect atmospheric pressure sensor.

Hint: Diagnostic trouble codes (DTCs) may be stored for the atmospheric pressure sensor; erase codes when fault-tracing is completed.

- Start the engine and idle it.
- Wait 5 minutes.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).

If EFI-621 is stored it should have intermittent status.

OK - Replacing component

Not OK - Replacing component

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Replacing component
- Try a new accelerometer.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Replacing component
- Try a new atmospheric pressure sensor.





Select "Continue" when the fault has been repaired.

Continue - Verification

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Replacing component
- Try a new air conditioning (A/C) pressure sensor.





Continue - Verification

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Verification




Verification

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












- Ignition off.
- Reconnect connectors and reinstall components.
- Disconnect the Volvo Scan Tool (ST) from the VIDA station and use it in stand-alone mode.
- Test drive the car.
- Use the Volvo Scan Tool (ST) to read off diagnostic trouble codes (DTCs).





If EFI-621 is stored it should have intermittent status.

OK - VERIFIED

Not OK - 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 diagnostic trouble codes (DTCs)

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