Part 2
Signal too low. Permanent fault (Continued)
EFI-621 Fuel tank pressure sensor, signal
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 -
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 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 -
Not OK -
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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 -
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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 -
Not OK -
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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 -
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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 -
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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 codes (DTCs).
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 power cable
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Checking power cable
- 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 3 (engine control module (ECM) side) and ground.
The ohmmeter should read approximately 0.2-1.5kohms.
OK - Checking the signal cable
Low - Checking accelerometer
High - Checking connector
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Checking accelerometer
- Ignition off.
- Tank pressure sensor disconnected.
- Disconnect accelerometer.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
The ohmmeter should read 0.2-1.5kohms
OK - Replacing component
Not OK - Checking the air conditioning (A/C) pressure sensor
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Replacing component
Try a new accelerometer.
Select Continue when the fault has been remedied.
Continue - Verification
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Checking the air conditioning (A/C) pressure sensor
- Ignition off.
- Fuel tank pressure sensor and accelerometer disconnected.
- Disconnect the air conditioning (A/C) pressure sensor.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
The ohmmeter should read 0.2-1.5kohms
OK - Replacing component
Not OK - Checking atmospheric pressure sensor
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Replacing component
Try a new air conditioning (A/C) pressure sensor.
Select Continue when the fault has been remedied.
Continue - Verification
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Checking atmospheric pressure sensor
- Ignition off.
- Fuel tank pressure sensor, accelerometer and air conditioning (A/C) pressure sensor disconnected
- Disconnect atmospheric pressure sensor
Connect an ohmmeter between fuel tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
The ohmmeter should read 0.2-1.5kohms
OK - Replacing component
Not OK - Checking short-circuit
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Replacing component
Try a new atmospheric pressure sensor.
Continue - Verification
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Checking short-circuit
- The fuel tank pressure sensor power cable is connected inside the engine control module (ECM) to the accelerometer and air conditioning (A/C) pressure sensor power cables.
If anything happens to any of these cables all three will be affected.
Check cables between:
- Tank pressure sensor terminal 3 and control module #B15.
- Accelerometer terminal 1 and control module #B1.
- Air conditioning (A/C) pressure sensor terminal 3 and control module #B29 for a short-circuit to ground. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Remedy as necessary.
Select Continue when the fault has been remedied.
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. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
- Control module connected.
- Reconnect connectors 24/2 and 24/4.
Connect an ohmmeter between fuel tank pressure sensor connector terminal 3 (engine control module (ECM) side) and ground.
The ohmmeter should read 0.2-1.5kohms
OK - Verification
Not OK - Checking cable
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Checking cable
Check voltage between fuel tank pressure sensor terminal 3 and control module #B15 for an open-circuit. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select Continue when the fault has been remedied.
Continue - Verification
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Checking the signal cable
- Tank pressure sensor disconnected.
- Ignition on.
Connect a voltmeter between the fuel tank pressure sensor connector terminal 2 (engine control module (ECM) side) and ground.
The voltmeter should read approximately 5-6 V.
OK - Replacing component
Not OK - Checking cable
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Checking cable
Check signal cable between fuel tank pressure sensor terminal 2 and control module B31 for an open-circuit. Checking wiring and terminals. Permanent fault Checking Wiring and Terminals. Permanent Fault.
Select Continue when the fault has been remedied.
Continue - Verification
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Replacing component
Try a new fuel tank pressure sensor according to Replacing fuel tank pressure sensor Removal and Replacement.
Select Continue when the fault has been remedied.
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 power cable
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