Testing:: Audi A8 D3

🧭 Before you start

Fits: Audi A8 D3 (4E, 2002–2010)

• Special tools named: VAS 5051

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• Depending on the control unit version, the vehicle diagnostic system display switches from e.g. "“Pipe filling”" to "“End”" or "“Function unknown or cannot be implemented at present”".
• One millilitre (ml) corresponds to 1/1000 litre or cm3.The specified delivery rate is obtained from the following arithmetic value (0.064 ml per stroke x 5 pulses per sec. x 250 sec.).

📋 Procedure

1. Select the supplementary heater control unit J364 in the "“Guided fault-finding”" function "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
2. Check the delivery rate of the metering pump V54"Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.
3. Observe the fuel entering the graduated beaker (B) from the fuel pipe (C). It must not contain any vapour bubbles. [Note: The metering pump V54 is actuated at a fixed clock frequency for the set time. During this test, fuel delivery is independent of instantaneous battery voltage.If the auxiliary/supplementary heater does not respond, switch on the ignition if applicable before selecting the supplementary heater control unit J364 again with the address word "“Supplementary/auxiliary heater”".Auxiliary/supplementary heater guided fault-finding can only be started with the ignition switched on or within a specified period after switching off the ignition or following the last exchange of data between the tester and a control unit (the data bus diagnostic interface J533 is not constantly active).On diesel vehicles with supplementary heater (without "“Auxiliary heater”" optional extra), the ignition must be left switched on, as otherwise self-diagnosis will be terminated.With the supplementary heater control unit J364 fitted at present, the maximum value which can be entered is "“255”".When checking the delivery rate, the metering pump V54 is actuated for 250 s at 5 hertz (5 pulses per second).The metering pump V54 actuation time is entered in seconds in the adaption channel. When the "“Pipe filling”" function is next selected in "“Basic setting”", the metering pump V54 is actuated for this period. The "“Pipe filling”" function can however only be performed in "“Basic setting”" if this has been enabled in a further adaption channel "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.Depending on the supplementary heater control unit J364, rounding errors on conversion after entering the encoded display value, e.g. "“250”", may lead to the following message being displayed "“Note: Value to be stored 250, value actually stored 249”". If this display appears, enter e.g. "“251”" instead of "“250”" if necessary to store the exact value and confirm the display.Values entered which are not within the specified limits are displayed but not implemented. If the value entered is too high or too low, the display is automatically reset (to the lowest or highest value still permitted).In the "“Pipe filling”" routine of the "“Basic setting”" function, the metering pump V54 is actuated at a frequency of 5 hertz (5 pulses per second). The delivery rate set in the metering pump V54 is approx. 0.064 ml per stroke (0.064/1000 litres).There may be several reasons for the display "“Function unknown or cannot be implemented at present”" appearing in the display zone "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.Once the "“Pipe filling”" function has been started, it cannot be terminated. It is implemented in full by the control unit regardless of any entries made by way of the tester.]
4. Wait until set time has elapsed and metering pump V54 is no longer actuated. [Note: Depending on the control unit version, the vehicle diagnostic system display switches from e.g. "“Pipe filling”" to "“End”" or "“Function unknown or cannot be implemented at present”".]
5. Terminate guided fault-finding "Guided fault-finding" function of vehicle diagnostic, testing and information system VAS 5051.

6. Measure the fuel delivery of the metering pump V54 on completion of the "“Basic setting”""“Pipe filling”" function. [Note: One millilitre (ml) corresponds to 1/1000 litre or cm3.The specified delivery rate is obtained from the following arithmetic value (0.064 ml per stroke x 5 pulses per sec. x 250 sec.).]
7. Re-install all the components removed on completion of the envisaged work.
8. Check the fuel pipe (from the fuel tank via the metering pump V54 to the auxiliary/supplementary heater) for damage and proper routing .
9. If no fault is found, replace metering pump V54.
10. In the event of auxiliary/additional heater starting problems despite correct fuel delivery, check CO2 content in exhaust gas .
11. If the fuel delivery is in the lower tolerance range (less than 74 ml) and there are starting problems with the auxiliary/supplementary heater or "“Poor heat output”" has been registered , replace the metering pump V54 if necessary .

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