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Home >> Audi >> 1996 >> Cabriolet V6-2.8L (AFC) >> Repair and Diagnosis >> Powertrain Management >> Computers and Control Systems >> Testing and Inspection >> Scan Tool Testing and Procedures >> Diagnosis With Scan Tool, Address Word 01 >> Read Measuring Block Values >> Display Group 030

Display Group 030

EVAP SYSTEM DIAGNOSIS









Notes:
- Display group 030 is only considered on vehicles with sensor for EVAP canister -G172-.
- If the value of the EVAP throughput diagnosis is not set to "0" in display group 029, display field 1 during regeneration of the readiness code, and/or there is a malfunction in DTC memory that relates to the EVAP system, display group 030 is used to carry out a selective diagnosis.
- Since the EVAP system is automatically shut off during "Basic Setting" function 04, display group 030 can only be evaluated using "Read Measuring Value Block" function 08.
- When diagnostic conditions are fulfilled, the Engine Control Module (ECM) checks the EVAP system at each start with the help of the sensor for EVAP canister -G172-. The pressure between the EVAP canister and EVAP canister purge regulator valve is measured with the sensor for EVAP canister -G172-.
- The diagnostic conditions are only fulfilled during a drive of approx. 1-1/2 to 5 minutes at 80-100km/h (50-63 mph) with manual transmission in 4th or 5th gear, or automatic transmission selector lever in "D" position, preferably in 4th gear; If the diagnostic conditions are fulfilled, the diagnosis is active. To get the diagnosis results, you have to drive approx. 1-1/2 to 5 minutes under the diagnostic conditions, while the pressure has to be measured with closed EVAP canister purge regulator valve. First, the pressure must be measured with the valve closed. You can get the valve to close most easily by having a preceding deceleration fuel shut-off. If there are problems in shutting the EVAP canister purge regulator valve by deceleration fuel shut-off, it can also be shut by running display group 030 in "Basic Setting" function 04. Then the pressure has to be measured again in "Read Measuring Value Block" function 08 with valve fully open.
- The diagnosis is recognized as OK if the EVAP system low pressure measured in display field 1 is greater than the actual calculated EVAP system minimum low pressure in display field 2.
- If the EVAP system is recognized as OK during the first diagnosis, the diagnosis is discontinued. If the EVAP system is recognized as not OK, the EVAP canister throughput test is continued.
- If the EVAP system throughput diagnosis is to be carried out selectively and/or after a diagnosis, shut the engine off and start again.

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