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Home >> Volvo >> 2000 >> C70 Convertible L5-2.3L Turbo VIN 53 B5234T3 >> Repair and Diagnosis >> A L L Diagnostic Trouble Codes ( DTC ) >> Testing and Inspection >> Manufacturer Code Charts >> ECM Codes (Engine Control Module) >> ECM-4019 >> Leak Diagnostic >> Part 1

Part 1






Leak diagnostic

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

Continue - Checking wiring and terminals

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Checking wiring and terminals
Check that the fuel tank filler cap is correctly secured. Check that seal of the filler cap is intact.
Then check the hoses and the hose connectors at the EVAP canister. Check the EVAP canister shut-off valve. Check the fuel tank.
Remedy as necessary.
Carry out a quick test of the fuel tank system.

Continue - General information about testing the fuel tank system

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General information about testing the fuel tank system
The engine management system has a built-in function for carrying out a quick check of fuel tank system sealing. By activating the function, the control module determines faster than usual whether the fuel tank system is fault free or if there is any leakage. The conditions for this test are that:
- Engine idling
- The engine coolant temperature (ECT) is higher than 70 °C
- There is not too much fuel in the tank
- Fuel evaporation is not too high during the leakage test (increased evaporation gives a pressure increase in the tank system).
The amount of vaporization permitted varies depending on the leakage test. Higher vaporization is permitted for the 1.0 mm than the 0.5 mm leakage test. If the test for 1.0 mm leaks starts but not for 0.5 mm leaks ("Smallest leak"), it may be because the fuel vaporization is too high.

Hint: There is high vaporization in warm conditions. Vaporization increases also if winter fuel is used in warm conditions. Fuel vaporization can be decreased by allowing the fuel to cool. If there is difficulty spray water on the fuel tank to speed up the fuel cooling down.

For further information about the fuel tank system diagnostic, see Leak diagnostic Leak Diagnostic.
1. Canister purge (CP) valve
2. EVAP canister
3. EVAP canister shut-off valve
4. Fuel tank pressure sensor
5. Air cleaner (ACL).

Location Of Components:






Continue - Checking the engine coolant temperature (ECT)

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Checking the engine coolant temperature (ECT)

Note! The test cannot be started if the engine coolant temperature (ECT) is below 70°C.




- Start the engine
- Read off the engine coolant temperature (ECT).
If the engine coolant temperature (ECT) is below 70°C, allow the engine to reach operating temperature or cancel the test.





Is the temperature above 70° C?

Yes - Starting the test of the fuel tank system

No - FAULT TRACING FAILED

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Starting the test of the fuel tank system

Note! The test cannot be started if the engine coolant temperature (ECT) is below 70°C.




- Engine idling
- Start the quick test.

Swift test running status
This parameter displays that the test is underway.
- RUNNING
- NOT RUNNING.

Fault status
These parameters display the status of those diagnostic tests which are included in the leak diagnostic.
- Status failure canister close valve
- Status failure rough leak
- Status failure PCV open
- Status failure small leak
- Status failure smallest leak.
The test runs in this order.
These parameters can assume three values depending on the test result.
- NOT READY
- READY NO FAULT
- READY FAULT FOUND.

Other parameters
- Fuel tank pressure (red line)
- EVAP canister shut-off valve, closes when it is active, ON (green line)
- Canister purge (CP) valve (yellow line).

Running order of the swift test
The complete swift test is run twice. The difference between the first run through and the second is that the "Small leak" is tested in the first run through and "Smallest leak" in the second run through.

Swift test starts with "Start reading"
The test starts and "RUNNING" is displayed in the status window. The test runs in the order above (see fault status).
The test is interrupted in three different ways, "NOT RUNNING".
- The test is ready
- The test has found a fault
- Physical faults in the car, for example the integral values go to the limit positions because of too great a volumetric efficiency in the EVAP canister.
The test is interrupted when the first run through is ready and no faults have been found. "READY NO FAULT FOUND" in the four left text boxes. By invalidating the idling conditions and returning to the idling conditions, the second run through starts. This is done by depressing and releasing the accelerator pedal (AP). The test starts again and the leak diagnostic is run through once more and "Smallest leak" is tested.
The test is complete when "READY NO FAULT FOUND" is displayed in all fault status windows at the same time that "NOT RUNNING" is displayed in the status window.
If the test has found a fault, "READY FAULT FOUND", the fault must be remedied for the test to be run through completely.
If the test is interrupted, "NOT RUNNING" is displayed in the status window and "NOT READY" is displayed in one of the test windows, the test must be started again: Switch off the engine and then start the engine and the swift test.

The following alternatives are available:
1. When the leak diagnostic is ready and the test has run without any faults being found, "READY NO FAULT FOUND" is displayed in all fault status windows
2. When the leak test has found a fault in the EVAP canister shut-off valve, "READY FAULT FOUND" is displayed in the fault status window for the EVAP canister shut-off valve
3. When the leak test has detected a major leak, "READY FAULT FOUND" is displayed in the fault status window for large leaks
4. When the leak test has found a fault in the canister purge (CP) valve, "READY FAULT FOUND" is displayed in the canister purge (CP) valve fault status window
5. When the leak test has detected a small leak or a very small leak, "READY FAULT FOUND" is displayed in the fault status window for small leak or smallest leak
6. The test does not start or is canceled before it is complete.





Select an alternative?

1 - FAULT FOUND

2 - Flow fault - Checking the fuel tank pressure sensor

3 - Large leak - Checking the vacuum downstream of the canister purge (CP) valve

4 - Leakage - Checking the vacuum downstream of the canister purge (CP) valve

5 - Checking for blockage between the fuel tank pressure sensor and the fuel tank

6 - Checking the cause of a fault using quick test

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Checking the cause of a fault using quick test

Hint: If the quick test does not start or is cancelled before it is complete it may be because
- the engine coolant temperature (ECT) is lower than 70°C
- there is too much fuel in the tank
- high fuel vaporization
- a blockage between the fuel tank pressure sensor and the fuel tank.
The method below is used to determine whether the cause of the problem is high vaporization or a blockage between the fuel tank pressure sensor and the fuel tank. It can be carried out by running the test with the fuel tank filler cap removed. Normally "large leak" is detected with the fuel tank filler cap removed.

Note! If the EVAP canister fills with the fuel vapor the test is interrupted. The EVAP canister fills with fuel vapor faster if the evaporative emission system (EVAP) valve is operating and the fuel tank filler cap is removed. Start the quick test directly after engine start and do not let the engine run at idle speed for longer than necessary.




- Remove the fuel tank filler cap
- Engine idling
- Start the quick test with the fuel tank filler cap removed.
In particular check the fuel tank pressure (red line) when the "large leak" test is running.
If quick test is not cancelled when the fuel tank filler cap is removed and "large leak" is detected after the quick test is complete, the fuel vaporization is too high. Fuel vaporization can be decreased by allowing the fuel to cool. If there is difficulty spray water on the fuel tank to speed up the fuel cooling down.
If quick test is cancelled or "small leak" is detected when the fuel tank filler cap is removed and the fuel tank pressure (red line) falls more quickly than normal during the test, it may be due to a blockage in the hose or hose terminal between the tank and the fuel tank pressure sensor. This can be fault-traced by removing the hoses to the evaporative emission (EVAP) system components one at a time and carrying out a quick test between each operation. If a "large leak" is detected after the quick test when the hose has been disconnected the fault is in the direction of the airflow (calculated from the hose that has been disconnected).

Hint: The direction of airflow during a quick test can be calculated from the fuel tank: fuel tank, evaporative emission system (EVAP) canister, evaporative emission system (EVAP) valve. The fuel tank pressure sensor measures the pressure in the hose between the fuel tank and the evaporative emission system (EVAP) canister.
If the hose for the EVAP canister is detached from the fuel tank and a "large leak" is detected, there is a blockage in the tank hose terminal.

Remedy as necessary.
Reset all the components. Carry out a quick test of the tank system before the car is delivered to the customer.

Select a suitable alternative to continue:
1. Continue the fault-tracing for the diagnostic trouble code (DTC)
2. Finish.










1 - Starting the test of the fuel tank system

2 - DONE

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Checking for blockage between the fuel tank pressure sensor and the fuel tank

Hint: If "small leak" is detected after a completed quick test of the fuel tank system, it may in certain cases be due to a blockage between the fuel tank pressure sensor and the fuel tank.
The method below is used to determine whether the detection of "small leak" after completed quick tests is caused by a blockage between the fuel tank pressure sensor and the fuel tank. It can be carried out by running the test with the fuel tank filler cap removed. Normally a "large leak" is detected with the fuel tank filler cap removed. If a "small leak" is detected with the fuel tank filler cap removed it indicates a blockage between the fuel tank pressure sensor and fuel tank.

Note! If the EVAP canister fills with the fuel vapor the test is interrupted. The EVAP canister fills with fuel vapor faster if the evaporative emission system (EVAP) valve is operating and the fuel tank filler cap is removed. Start the quick test directly after engine start and do not let the engine run at idle speed for longer than necessary.




- Remove the fuel tank filler cap
- Engine idling
- Start the quick test with the fuel tank filler cap removed.
In particular check the fuel tank pressure (red line) when the "large leak" test is running.
If a "large leak" is detected with the fuel tank filler cap removed, the most likely cause is leakage. Continue fault-tracing according to "small leak".
If the test is cancelled or "small leak" is detected with the fuel tank filler cap removed and the fuel tank pressure (red line) falls more slowly than normal during the test it may be due to a blockage in the hose or hose terminal between the tank and the fuel tank pressure sensor. This can be fault-traced by removing the hoses to the evaporative emission (EVAP) system components one at a time and carrying out a quick test between each operation. If a "large leak" is detected after the quick test when the hose has been disconnected the fault is in the direction of the airflow (calculated from the hose that has been disconnected).

Hint: The direction of airflow during a quick test can be calculated from the fuel tank: fuel tank, evaporative emission system (EVAP) canister, evaporative emission system (EVAP) valve. The fuel tank pressure sensor measures the pressure in the hose between the fuel tank and the evaporative emission system (EVAP) canister.
If the hose for the EVAP canister is detached from the fuel tank and a "large leak" is detected, there is a blockage in the tank hose terminal.

Remedy as necessary.
Reset all the components. Carry out a quick test of the tank system before the car is delivered to the customer.

Select a suitable alternative to continue:
1. Continue "small leak" fault-tracing
2. Finish.










1 - Small leak - Test pressurization of the fuel tank system

2 - DONE

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Large leak

Checking the vacuum downstream of the canister purge (CP) valve




- Start the engine and let it run at idle speed.
- Disconnect the hose between the canister purge (CP) valve and the EVAP canister from the canister purge (CP) valve.
- Read off the canister purge (CP) valve. This is to check whether the valve is activated.
Check that there is a vacuum in the canister purge (CP) valve when the valve is activated.









Is there a vacuum?

Yes - Checking the vacuum at the EVAP canister

No - Checking the canister purge (CP) valve vacuum

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Checking the vacuum at the EVAP canister




- Ignition off.
- Reconnect the hose on the canister purge (CP) valve.
- Disconnect the hose to the canister purge (CP) valve from the EVAP canister.
- Start the engine and let it run at idle speed.
- Read off the canister purge (CP) valve value. This is to determine whether the valve is activated or not.
Check that there is a vacuum in the hose when the canister purge (CP) valve is activated.









Is there a vacuum?

Yes - Checking the EVAP canister

No - Checking the hose

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