Audi Workshop Service and Repair Manuals

Test requirements:

• ‒ Coolant temperature less than 30 °C.
• ‒ Ambient temperature less than 20 °C.
• ‒ If the fault memory was interrogated and any displayed faults rectified.

Note:

A higher ambient temperature can lead to errors in the measured fuel quantity due to fuel evaporation.

• ‒ The battery -A- is OK and adequately charged.
• ‒ Sufficient fuel in tank (fuel gauge in dash panel insert is not in red zone).

Checking:

• ‒ Switch ignition off.

• ‒ → Remove the fuel pipe -A- from the additional heater.
• ‒ Attach a graduated beaker -B- near fuel line using e.g. wire and route the fuel line into the graduated beaker.

Note:

If necessary, extend fuel line using a plastic tube -C-.

• ‒ Initiate self-diagnosis for the additional heater and select the function "Basic setting"

→ Display on VAS 5051:

• ◆ The prompt to enter a display group is given in display zone -1-.
• ◆ An input keyboard is displayed in display zone -2-.

• ‒ Enter "055" for "display group number 55" using the input keyboard in display zone -2- and confirm entry with "Q key".

→ Display on VAS 5051:

• ◆ The function "display group 55, System in basic setting" is displayed in display zone -1-.
• ◆ The "Pipe filling" function is displayed in area -2-.

The metering pump -V54 is actuated at a fixed clock frequency

Notes:

• ◆ The metering pump -V54 is now activated for 50 sec. "first run" (clock frequency 5 Hz).
• ◆ If the "Pipe filling" function has been initiated, the function cannot be interrupted, it is carried out in its entirety by the control unit regardless of any input via the test unit.
• ◆ The function "line filling" must be performed 3 times. If the line is filled completely after 1st run the quantity is measured during the 2nd and 3rd run (due to the low delivery rate 2 runs of 50 seconds each are necessary to increase accuracy of the measurement).

• ◆ → If the message "Function unknown or cannot be executed at present" appears in display zone -1- this may have the following cause:

• ‒ The additional heater was switched on and is currently in "run-on" operating status.
• ‒ A fault is stored in the additional heater which does not permit switching on.

• ◆ Change to a different function (e.g. from "Basic setting" to "Read measured value block") by pressing the -3- key (you return to the "Basic setting" by pressing the -4- key).

• ‒ Wait until the display in area -2- changes from "Pipe filling" to "End".

• ‒ Empty graduated beaker and reattach it.
• ‒ Press the ←keyin the display of the VAS 5051.

→ Display on VAS 5051:

• ‒ Enter "055" for "display group number 55" using the input keyboard in display zone -2- and confirm entry with "Q key".

• ‒ Wait until the display in area -2- changes from "Pipe filling" to "End".

Note:

The metering pump -V54 is now activated for 50 sec. "second run" (clock frequency 5 Hz).

• ‒ Press the ←keyin the display of the VAS 5051.
• ‒ Perform the "Pipe filling" function again.

Note:

The metering pump -V54 is now actuated for 50 seconds, "third run" (clock frequency 5 Hz).

• ‒ Wait until the display in area -2- changes from "Pipe filling" to "End".

Note:

The metering pump -V54 should be activated for 100 sec. in order to obtain an accurate measurement (2 "pipe filling" procedures).

• ‒ After the third pipe filling procedure has been completed, measure metering pump fuel delivery rate.

Specified value:

29 to 35 cm3 (millilitres)

Notes:

• ◆ The fuel delivery rate during this test is independent of the current battery voltage (the delivery rate is stabilised by the control unit -J162).
• ◆ Bubbles of vapour should not be present.
• ◆ If the fuel delivery rate is outside the tolerance range:
• ‒ Check fuel line for damage and proper routing => Page 82-15
• ‒ If no fault can be found, replace -V54 metering pump
• ◆ If the additional heater has starting difficulties although the fuel delivery rate is OK, check of CO2-content in exhaust gas => Page 82-27