Fault-Tracing Information
Fault-tracing
Perform quick-test tank system
- Activate the test by pressing on the symbol for VCT2000.
- Read off initial parameters and check them according to start conditions for performing the test.
- Press the button "Start" to start the quick-test.
- Check that the test has started. Parameters run status shall go to "In progress" and the test phase shall go to "Reference".
Note! If the test does not start, check that the start conditions are fulfilled.
When the reference phase is finished, check of the tank system starts. The pressure in the tank starts to increase, see graph. Within 15 minutes the Engine control module (ECM) makes a decision as to whether there is leakage in the tank system or not. The test is finished.
- Check parameters for test result and follow relevant instructions below.
Note! Estimated leakage shall be used to get an idea of the proximity to the diagnostic trouble code limit. If the estimated leakage is very near the diagnostic trouble code limit, troubleshooting should probably be performed despite the Tank system, test result shows "No leakage found", especially if diagnostic trouble code for leakage has been stored earlier.
Note! Use diagnostic trouble code counter to see the frequency of the problem. Also use frozen values to get an idea if external conditions may have affected the result. Compare with current conditions in the workshop.
Conditions for starting the quick test of the fuel tank system
- No DTCs related to EVAP purge valve or ambient air pressure sensor set.
- Battery voltage 11-15 V.
- Atmospheric pressure higher than 750 hPa, appr. 2500 m (8200 ft).
- Fuel level 0-85 %.
- Ambient air temperature 4-35 °C (39-95 °F).
Note! The battery voltage must be correct throughout the entire test. The test can take up to 15 minutes, depending on the quantity of fuel in the fuel tank. It is highly recommended to use the constant voltage charger, Midtronics PSC-550, during the test. For more information, see TNN 30-04 (USA/CDN).
Other information
- Description of parameters, quick test of the fuel tank system, B6304T4 Description Of Parameters, Quick Test Of The Fuel Tank System
- Test phases, quick test fuel tank system, B6304T4 Test Phases, Quick Test Fuel Tank System
- For information on leakage diagnosis, see Design and Function.
- Location of components, B6304T4 Locations
Select alternative according to relevant test results:
1. DMTL, test result = "Problem found"
2. Tank system, test result = "No leakage found"
3. Tank system, test result = "Minor leakage found"
4. Tank system, test result = "Major leakage found"
5. DMTL, test result and Tank system, test result = "Unknown"
6. Cancel fault-tracing.
1 - DMTL, test result = "Problem found"
2 - Tank system, test result = "No leakage found"
3 - Tank system, test result = "Minor leakage found"
4 - Tank system, test result = "Major leakage found"
5 - DMTL, test result and Tank system, test result = "Unknown"
6 - No Fault Found
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DMTL, test result = "Problem found"
If a problem is detected on the leakage diagnostics unit (DMTL), this may have been caused during the test itself. Checks on DMTL are normal electric checks of leakage diagnostics unit and cabling and is no indication of if there is leakage or not.
- Cancel troubleshooting for this problem.
- Read off diagnostic trouble codes again and start troubleshooting for the new diagnostic trouble code.
Note! The tank system's status is unknown since the test was interrupted.
Continue - ANOTHER TEST
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Tank system, test result = "No leakage found"
Diagnostic trouble code limit (minor leakage): Estimated leakage = 0.40 mm
If no leakage was found, the Engine control module (ECM) has detected leakage in the tank system earlier, but the problem is not active at this time. The fault could be caused by leakage in the tank, filler pipe, fuel tank filler cap, canister, EVAP valve, leakage diagnosis unit or hoses between these components.
Note! Problems caused by a loose tank cap or loose hose connections may be difficult to find. If no leakage was found in the quick-test of the tank system after completed checks and actions according to the above, the problem has likely been repaired.
Note! The parameter estimated leakage does not necessarily have to show 0 mm for a sealed system.
Continue - FAULT FOUND
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Tank system, test result = "Minor leakage found"
Diagnostic trouble code limit: Estimated leakage = 0.40 mm
- Check that the tank cap is properly fitted and that its seal is undamaged.
- Check the hoses and connections on the leak diagnostic unit, the canister,EVAP-valve and the fuel filler pipe visually. Check for damage or incorrect/loose installation.
- Remedy as necessary.
- Restart the test.
Note! Problems caused by a loose tank cap or loose hose connections may be difficult to find. If no leakage was found in the quick-test of the tank system after completed checks and actions according to the above, the problem has likely been repaired.
Note! By blocking the hose between canister and EVAP-valve and then repeating quick-test tank system, leakage through the EVAP-valve can be detected. If leakage was detected in a previous quick test of the fuel tank system but is not now detected when the hose between the canister and the EVAP valve is blocked, the leakage may be through the EVAP valve.
- Disconnect the hose between the EVAP canister purge valve and the EVAP canister from the connection to the EVAP canister purge valve.
- Block the hose while running the quick test of the fuel tank system.
Continue - Perform quick-test tank system
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DMTL, test result and Tank system, test result = "Unknown"
Engine control module (ECM) cannot perform check of tank system. This may be due to the conditions for start of the quick-test not being fulfilled,that they have changed during the course of the test, or that a problem has occurred during troubleshooting.
- Check that all conditions for start of the quick-test are fulfilled.
- Visually check hoses and connections on leakage diagnostics unit, canister, EVAP-valve, and filler pipe. Check for damage or incorrect/loose installation.
- Remedy as necessary.
- Restart the test.
Continue - Perform quick-test tank system
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Tank system, test result = "Major leakage found"
Diagnostic trouble code limit: Tank pressure lower than 1500 Pa after 450 seconds in test phase "Major leakage".
- Check that the tank cap is properly fitted and that its seal is undamaged.
- Check the hoses and connections on the leak diagnostic unit, the canister,EVAP-valve and the fuel filler pipe visually. Check for damage or incorrect/loose installation.
- Remedy as necessary.
- Restart the test.
Note! Problems caused by a loose tank cap or loose hose connections may be difficult to find. If no leakage was found in the quick-test of the tank system after completed checks and actions according to the above, the problem has likely been repaired.
Continue - Perform quick-test tank system
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