Operation CHARM: Car repair manuals for everyone.

Part 2






Signal too high. Permanent fault (Continued)

EFI-621 Fuel tank pressure sensor, signal

Checking for an open-circuit




- Check cable between connector 24/2 terminal C6 and connector 24/4 terminal E5 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue -

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Checking control module connector












- Ignition off.
- Tank pressure sensor disconnected.
- Connector 24/2 disassembled.
- 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.
- Control module connected.
- Ignition on.
Connect a voltmeter between connector 24/2 terminal C6 and ground.





The voltmeter should read approximately 5 V.

OK -

Not OK -

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Fault-tracing information
- The diagnostic trouble code (DTC) was caused by loose connections in the engine control module (ECM) connector.

Continue -

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Checking for an open-circuit




- Check cable between connector 24/2 terminal C6 and engine control module (ECM) #B31 for an open-circuit according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue -

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Checking fuel tank pressure sensor












- Ignition off.
- Connect fuel tank pressure sensor.
- Start the engine and idle it for a minute.




- Select Volvo Scan Tool (ST) to read off diagnostic trouble code (DTC).

If a diagnostic trouble code (DTC) is stored it should have intermittent status.

OK -

Not OK -

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Replacing component
- Try a new fuel tank pressure sensor according to Tank pressure sensor, replacement Removal and Replacement.





Continue -

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Checking for contact resistance and oxidation








- The diagnostic trouble code (DTC) has been caused by loose connections in the fuel tank pressure sensor connector. Check connector for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue -

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Verification




Verification

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












- Ignition off.
- Ensure that fuel tank pressure sensor, air conditioning (A/C) pressure sensor, accelerometer and engine control module (ECM) are connected.
- Connectors 24/2 and 24/4 connected.
- Ignition on.
Select Volvo Scan Tool (ST) to erase diagnostic trouble codes (DTCs).





Continue - Verification, continued

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Verification, continued




- Start the engine and idle it.




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

Does the diagnostic trouble code (DTC) recur?

Yes - VERIFICATION FAILED

No - VERIFIED

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VERIFIED - FAULT FOUND

VERIFICATION FAILED -

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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 -

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Safety
First read Safety regulations for handling fuel Safety Regulations For Handling Fuel.

Continue - Checking ground lead

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Checking ground lead








- Ignition off.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disconnect tank pressure sensor.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 1 (engine control module (ECM) side) and ground.









The ohmmeter should read approximately 0 ohms.

OK - Checking the signal cable

Not OK - Checking connector

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Checking connector








- Ignition off.
- Tank pressure sensor disconnected.
- Check connector 24/4 for contact resistance and oxidation. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Control module connected.
- Assemble connector 24/4.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 1 (engine control module (ECM) side) and ground.









The ohmmeter should read approximately 0 ohms.

OK - Verification.

Not OK - Checking cable

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Checking cable
Check ground lead between fuel tank pressure sensor terminal 2 and control module terminal #B28 for an open-circuit. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Remedy as necessary.













Continue - Verification

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Checking the signal cable




- Ignition on.
- Tank pressure sensor disconnected.
Connect a voltmeter between fuel tank pressure sensor connector terminal 2 (engine control module (ECM) side) and ground.









The voltmeter should read 5-6 V.

OK - Checking fuel tank pressure sensor

Low - Checking connector

High - Checking cable

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Checking cable
Check signal cable between fuel tank pressure sensor terminal 2 and engine control module (ECM) terminal #B31 for a short-circuit to supply voltage. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault. Remedy as necessary.













Continue - Verification

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Checking connector




- Ignition off.
- Tank pressure sensor disconnected.
- Check control module connector and connectors 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.
- Control module connected.
- Connect connectors 24/2 and 24/4.
- Ignition on.
Connect a voltmeter between tank pressure sensor connector terminal 2 (engine control module (ECM) side) and ground.









The voltmeter should read approximately 5 V.

OK - Verification

Not OK - Checking cable

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Checking cable
Check signal cable between fuel tank pressure sensor terminal and control module terminal #B31 for an open-circuit. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.













Continue - Verification

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Checking fuel tank pressure sensor




- Ignition off.
- Connect fuel tank pressure sensor.
- Start the engine and idle it for a minute.
Read diagnostic trouble code (DTC) status message.





Is an intermittent fault displayed?

Yes - Remedy connector

No - Replacing component

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Replacing component
Try a new fuel tank pressure sensor according to Replacing fuel tank pressure sensor Removal and Replacement.

Continue - Verification

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Remedy connector
The diagnostic trouble code (DTC) has been caused by loose connections in the fuel tank pressure sensor connector. Check the connector for contact resistance and oxidation and remedy. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.

Continue - Verification

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Verification




Verification

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




- Ignition off.
- Ensure that fuel tank pressure sensor, air conditioning (A/C) pressure sensor, accelerometer and engine control module (ECM) are connected.
- Connectors 24/2 and 24/4 are connected.
- Start the engine and idle it.
If EFI-621 is stored it should have intermittent status.





Does EFI-621 have intermittent status?

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
Attempt New Test - Checking ground lead

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