View source for Readiness Test (UDS only)

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= Readiness Test (UDS only) =
* This Tech Tip demonstrates how to perform the [Automatic test sequence] for UDS-based ''Gasoline'' Engine Control Modules (ECMs) using VCDS.
* Basic Setting performs the required Readiness Tests on modern VW/Audi vehicles equipped with UDS protocol engine controllers.
* Use of this procedure is typically for after repairs or component replacement affecting emissions-related systems, or after clearing DTCs.

==== Special Tools ====
* VCDS (VAG-COM Diagnostic System)

==== Prerequisites ====
* Engine must be running
* All electrical consumers OFF (A/C, headlights, rear defrost, seat heaters, etc.)
* No active Diagnostic Trouble Codes (DTCs) – Clear all fault codes prior to starting the test
* Engine coolant temperature must be at least 80°C (176°F)
* <span style="color:red;">Must be performed outside or in a well-ventilated area, and never park the vehicle over combustible materials.</span>

==== Workshop Procedure with VCDS ====

* Connect to the vehicle using VCDS.

* Go to '''[01 - Engine]'''

* Check for and clear any fault codes.

* Click on the '''[Basic Settings]''' button.

* Select '''[Automatic test sequence]''' or '''[Automatic test procedure]''' from the available list.

* Click on the '''[Show Measuring Data]''' checkbox and include the following Measuring Values:

  {| class="wikitable"
  |-
  ! Measuring Value !! Description
  |-
  | IDE00450 || '''Operating Instructions''' – ''Follow all prompts provided here''
  |-
  | IDE00451 || '''Currently Running Routine''' – ''Indicates the test currently in progress''
  |-
  | IDE00030 || '''Status of Actuator Test''' – ''Displays overall status of test procedure''
  |-
  | IDE00727 || '''Test Steps Still to Be Performed''' – ''Should count down to 0 when complete''
  |-
  | IDE00021 || '''Engine Speed''' – ''Follow any required RPM prompts shown in Operating Instructions''
  |-
  | IDE00025 || '''Coolant Temperature''' – ''Should be at or above 80°C before beginning''
  |}

* Click the '''[Go]''' button to begin the Basic Setting procedure.

* When prompted, '''press and hold both the brake and accelerator pedals simultaneously.''' Keep them pressed until the test finishes.

* When the test completes successfully, the '''IDE00450 [Operating Instructions]''' field will display:  
  ''''System OK''''   or   ''''Finished correctly''''


==== Special Notes ====

* The duration of the Automatic Test Sequence may vary depending on vehicle platform and engine type.
* If the sequence fails or does not complete, verify that all prerequisites are met, especially coolant temperature and fault-free status.
* This function is only available in UDS-based engine control modules. Non-UDS controllers use a different Readiness procedure, see Repair Manual.
* If the [Go] button is grayed out or unavailable, ensure that the engine is running and that the selected test is supported by the ECU.
* Using VCDS initiates a request to perform the readiness test; the ECU controls the process and may take longer to complete as the vehicle ages.
* Ensure the engine control module has the latest software version installed to avoid readiness issues.
* In some cases, it may be necessary to complete a full OBD drive cycle before attempting the readiness procedure again.



[[Category:Tech Tips]]