Part 2
Leak diagnostic (Continued)
Checking the canister purge (CP) valve vacuum
- Connect the hose between the canister purge (CP) valve and the EVAP canister to the canister purge (CP) valve.
- Start the engine and let it idle.
- Disconnect the hose between the canister purge (CP) valve and the intake manifold from the canister purge (CP) valve.
Check that there is a vacuum in the hose.
Remedy as necessary.
Was a fault detected?
Yes - ANOTHER TEST
No - Replacing the component
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Replacing the component
Try a new canister purge (CP) valve according to Replacing the canister purge (CP) valve Service and Repair.
Continue - ANOTHER TEST
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Checking the EVAP canister
Check that all EVAP canister inlets and outlets are not sealed.
Hint: Connect a vacuum pump to the EVAP canister terminals, one at a time. Check that negative pressure cannot be pumped.
Other information:
- To access and replace the EVAP canister (C70/S70/V70), see the relevant service procedure.
Was a fault detected?
Yes - ANOTHER TEST
No - Checking the hose between the fuel tank and the EVAP canister
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Checking the hose
Check if the hose between the canister purge (CP) valve and the EVAP canister is blocked or trapped.
Continue - ANOTHER TEST
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Checking the hose between the fuel tank and the EVAP canister
Check that the hose between the fuel tank and EVAP canister is airtight and is not trapped.
Remedy as necessary.
Was a fault detected?
Yes - ANOTHER TEST
No - Test pressurization of the fuel tank system
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Test pressurization of the fuel tank system
- Max 50 liters of fuel in the fuel tank.
- Ignition off.
- Connect the hose from the fuel tank to the EVAP canister.
- Clamp the hose between the EVAP canister shut-off valve and the EVAP canister with a hose clip to seal it.
- Carefully disconnect the EVAP canister hose from the canister purge (CP) valve.
Connect manometer999 5646 Pressure gauge 999 5646 Pressure Gauge to the hose and the pressure regulator999 5544 REGULATOR 999 5544 Regulator to the manometer.
Set the pressure to 7 kPa (read off on manometer999 5646 Pressure gauge 999 5646 Pressure Gauge ).
The cock must be at right angles to the hoses.
Warning! Max 10 kPa.
Let the pressure build up for 5 minutes.
Shut off the cock (the pressure may drop 1-2 kPa before stabilizing). Read off the pressure.
Turn the cock towards the EVAP canister hose.
Wait for 10 minutes.
Warning! Never leave the car unattended with its fuel tank system pressurized.
The pressure must be stable (it may rise a little due to fuel evaporation).
Is the pressure stable?
Yes - Checking the fuel tank pressure sensor
No - Checking the fuel tank system
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Checking the fuel tank pressure sensor
- Disconnect tool999 5646 Pressure gauge 999 5646 Pressure Gauge.
- Connect the EVAP canister hose.
- Remove the hose clamp from the hose between the canister purge (CP) valve and the intake manifold.
- Start the engine and let it idle.
- Read off the value for the fuel tank pressure and the canister purge (CP) valve.
When the canister purge (CP) valve opens, the pressure in the fuel tank must drop.
Is the pressure in the fuel tank dropping?
Yes - Checking the hose to the EVAP canister shut-off valve
No - Checking the fuel tank pressure sensor hose
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Checking the hose to the EVAP canister shut-off valve
Check the hose to the EVAP canister shut-off valve. Check the seal. Check the terminals.
Remedy as necessary.
Was a fault detected?
Yes - ANOTHER TEST
No - Replacing the component
------------------------
Checking the fuel tank pressure sensor hose
- Ignition off.
- Remove the fuel tank pressure sensor.
- Remove the hose with the Y-nipple.
Check that the nipple and hoses are not blocked.
Remedy as necessary.
Other information:
- To access and replace the fuel tank pressure sensor (C70/S70/V70), see Replacing fuel tank pressure sensor Service and Repair.
Was a fault detected?
Yes - ANOTHER TEST
No - Replacing the component
------------------------
Replacing the component
Try a new fuel tank pressure sensor (C70/S70/V70) according to Replacing fuel tank pressure sensor Service and Repair.
Continue - ANOTHER TEST
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Replacing the component
Try a new EVAP canister shut-off valve (C70/S70/V70) .
Continue - ANOTHER TEST
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Checking the fuel tank system
- Ignition off.
- Carefully pressurize the fuel tank system to 7 kPa. The cock must be at right angles to the hoses.
Note! Max 10 kPa.
Check the fuel tank system: Spray soapy water from the EVAP canister to the canister purge (CP) valve. Also spray the line between the fuel tank and the EVAP canister shut-off valve. Also check the filler pipe and the fuel tank filler cap.
It may be necessary to lower the fuel tank in order to fault-trace hoses and connectors on top of the fuel tank.
Remedy the leakage.
Continue - ANOTHER TEST
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ANOTHER TEST - Verification information
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Small leak
Small leak
Test pressurization of the fuel tank system
- Max 50 liters of fuel in the fuel tank.
- Ignition off.
- Clamp the hose between the EVAP canister shut-off valve and the EVAP canister with a hose clip to seal it.
- Carefully disconnect the EVAP canister hose from the canister purge (CP) valve.
Connect manometer999 5646 Pressure gauge 999 5646 Pressure Gauge to the hose and the pressure regulator999 5544 REGULATOR 999 5544 Regulator to the manometer.
Set the pressure to 7 kPa (read off on the manometer999 5646 Pressure gauge 999 5646 Pressure Gauge.
The cock must be at right angles to the hoses.
Warning! Max 10 kPa.
Let the pressure build up for 5 minutes.
Close the cock (the pressure may now drop by 1-2 kPa before it stabilizes). Read off the pressure.
Turn the cock towards the EVAP canister hose.
Wait for 10 minutes.
Warning! Never leave the car unattended with its system pressurized.
The pressure must be stable (it may rise a little due to fuel evaporation).
Is the pressure stable?
Yes - Checking the hose to the EVAP canister shut-off valve
No - Checking the fuel tank system
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Checking the hose to the EVAP canister shut-off valve
Check the hose to the EVAP canister shut-off valve. Check the seal. Check the terminals.
Remedy as necessary.
Is the hose OK?
Yes - Replacing the component
No - ANOTHER TEST
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Replacing the component
Try a new EVAP canister shut-off valve .
Continue - ANOTHER TEST
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Checking the fuel tank system
- Ignition off.
- Carefully pressurize the fuel tank system to 7 kPa.
Turn the EVAP canister shut-off valve so that it is at a right angle to the hoses.
Warning! Max 10 kPa
Check the fuel tank system by spraying it with soapy water from the EVAP canister to the canister purge (CP) valve. Also spray the line with the pressure regulator and roll-over valve to the fuel tank. Also check the filler pipe and the fuel tank filler cap.
It may be necessary to lower the fuel tank in order to fault-trace hoses and connectors on top of the fuel tank.
Warning! Never leave the car unattended with its system pressurized.
Continue - ANOTHER TEST
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ANOTHER TEST - Verification information
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Verification information
Verification information
Verification information
Hint: After carrying out the check and the repair, check that the fault has been remedied.
Press continue for verification.
Continue - ANOTHER TEST
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ANOTHER TEST - Starting the quick test
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Canister purge (CP) valve
Leakage
Checking the vacuum downstream of the canister purge (CP) valve
- Disconnect the hose between the canister purge (CP) valve and the EVAP canister from the canister purge (CP) valve.
- Start the engine and let it idle.
Hint: Listen to or feel the valve to ensure that it is not activated. The signal can be stopped and read off in the event of uncertainty. Feel with fingers or connect a vacuum gauge to the valve connection to determine whether there is leakage when the canister purge (CP) valve is off. There must not be any leakage.
Other information:
- To access or replace the canister purge (CP) valve, see Replacing the canister purge (CP) valve Service and Repair.
Is the canister purge (CP) valve OK?
Yes - Checking the canister purge (CP) valve
No - ANOTHER TEST
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Checking the canister purge (CP) valve
Check the canister purge (CP) valve connector for dirt, damage and deposits.
Activate the canister purge (CP) valve to ensure that no function faults occur.
Check that the canister purge (CP) valve does not jam or stop functioning after it has been activated.
Continue - ANOTHER TEST
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ANOTHER TEST - Verification information
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EVAP canister shut-off valve
Flow fault
Checking the fuel tank pressure sensor
- Open the fuel tank filler cap.
- Start the engine and let it idle.
Read off the fuel tank pressure.
Hint: The fuel tank pressure must be higher than -10 hPa. The normal value is close to 0 hPa. If uncertain of the function of the fuel tank pressure sensor, try connecting another fuel tank pressure sensor.
Remedy as necessary.
Is the fuel tank pressure OK?
Yes - Checking the canister purge (CP) valve
No - ANOTHER TEST
------------------------
Checking the canister purge (CP) valve
- Disconnect the hose between the canister purge (CP) valve and the EVAP canister from the canister purge (CP) valve.
- Start the engine and let it idle.
Hint: Listen to or feel the valve to ensure that it is not activated. The signal can be stopped in the event of uncertainty. Feel with fingers or connect a vacuum gauge to the valve connection to determine whether there is leakage when the canister purge (CP) valve is off. There must not be any leakage.
Other information:
- To access or replace the canister purge (CP) valve, see Replacing the canister purge (CP) valve Service and Repair.
Is the canister purge (CP) valve OK?
Yes - Checking hoses
No - ANOTHER TEST
------------------------
Checking hoses
Check whether the EVAP canister shut-off valve is not sealed.
Check whether the EVAP canister shut-off valve filter is not sealed.
Check the hose between the EVAP canister and the EVAP canister shut-off valve. Check the hose between the EVAP canister shut-off valve and its filter. Check whether these hoses are not sealed.
Check whether the EVAP canister shut-off valve terminal in the EVAP canister is not sealed.
Remedy as necessary.
Other information:
- To access or replace the EVAP canister shut-off valve, see the relevant service procedure.
Continue - ANOTHER TEST
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ANOTHER TEST - Verification information
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