Part 2
Signal too low: Permanent fault (Continued)
EFI-621 Fuel tank pressure sensor, signal
Checking the signal cable
- Ignition off.
- Tank pressure sensor disconnected.
- Ignition on.
Connect a voltmeter between tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 6 V.
OK - Checking fuel tank pressure sensor
Not OK - Checking signal cable resistance to ground
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Checking signal cable resistance to ground
- Ignition off.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Tank pressure sensor disconnected.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
Does the ohmmeter read infinite resistance?
Yes - Checking connector 24/4
No - Checking signal cable between fuel tank pressure sensor and connector 24/4
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Checking connector 24/4
- Ignition off.
- Tank pressure sensor disconnected.
- Check connector 24/4 for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Assemble connector 24/4.
- Ignition on.
Connect a voltmeter between tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 6 V.
OK - Fault-tracing information
Not OK - Checking signal cable between connector 24/4 and fuel tank pressure sensor
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Fault-tracing information
- The diagnostic trouble code (DTC) has been caused by loose connections in connector 24/4.
Continue - Verification
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Checking signal cable between connector 24/4 and fuel tank pressure sensor
- Tank pressure sensor disconnected.
- Disassemble connector 24/4.
- Ignition on.
Connect a voltmeter between connector 24/4 terminal E5 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 6 V.
OK - Checking for an open-circuit
Not OK - Checking connector 24/2
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Checking for an open-circuit
- Check cable between fuel tank pressure sensor terminal 3 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 - Verification
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Checking connector 24/2
- Ignition off.
- Tank pressure sensor disconnected.
- Connector 24/4 disassembled.
- Check connector 24/2 for contact resistance and oxidation and remedy according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Assemble connector 24/2.
- Ignition on.
Connect a voltmeter between connector 24/4 terminal E5 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 6 V.
OK - Fault-tracing information
Not OK - Checking signal cable between connector 24/4 and 24/2
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Fault-tracing information
- The diagnostic trouble code (DTC) has been caused by loose connections in connector 24/2.
Continue - Verification
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Checking signal cable between connector 24/4 and 24/2
- Disassemble connector 24/2.
- Ignition on.
Connect a voltmeter between connector 24/2 terminal C6 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 6 V.
OK - Checking for an open-circuit
Not OK - Checking control module connector
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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 - Verification
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Checking control module connector
- Ignition off.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- 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.
- Connect control module.
- Ignition on.
Connect a voltmeter between connector 24/2 terminal C6 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 6 V.
OK - Fault-tracing information
Not OK - Checking for an open-circuit
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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 - Verification
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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 - Verification
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Checking signal cable between fuel tank pressure sensor and connector 24/4
- Ignition off.
- Wait for approximately 150 seconds (cars with immobilizer 245 seconds).
- Disassemble connector 24/4.
Connect an ohmmeter between connector 24/4 terminal E5 (engine control module (ECM) side) and ground.
The ohmmeter should read between 0.5 Mohms and infinite resistance.
OK - Checking for a short-circuit
Not OK - Checking signal cable between connector 24/4 and 24/2
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Checking for a short-circuit
- Check cable between fuel tank pressure sensor terminal 3 and connector 24/4 terminal E5 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Continue - Verification
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Checking signal cable between connector 24/4 and 24/2
- Ignition off.
- Disassemble connector 24/2.
Connect an ohmmeter between connector 24/2 terminal C6 (engine control module (ECM) side) and ground.
The ohmmeter should read between 0.5 Mohms and infinite resistance.
OK - Checking for a short-circuit
Not OK - Checking for a short-circuit
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Checking for a short-circuit
- Check cable between connector 24/4 terminal E5 and connector 24/2 terminal C6 for a short-circuit to ground according to Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Continue - Verification
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Checking for a short-circuit
- Check signal cable between connector 24/2 terminal C6 and control module #B31 for a short-circuit to ground according to 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.
- Select Volvo Scan Tool (ST) to read off diagnostic trouble code (DTC).
Has the diagnostic trouble code (DTC) "Permanent" status?
Yes - Replacing component
No - Checking for contact resistance and oxidation
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Replacing component
- Try a new fuel tank pressure sensor.
Continue - Verification
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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 - Verification
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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 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 power cable
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