Display Group 023

DISPLAY GROUP 023
Diagnostic Status

NOTES:
OBD II regulations require a "Readiness Code" that displays inspection readiness. The Readiness Code shows that each component and/or system that influences exhaust emissions and can switch the Malfunction Indicator Lamp (MIL) on has been operated at least once with positive results.

The Readiness Code is reset or erased:
^ Every time DTC memory is erased (with address word 01, function 05, or with address word 33, mode 4)
^ When the battery (B+) is disconnected
^ When the connector is disconnected from the ECM

To create the "Readiness Code" a "mixed city and highway" drive at 50-62 mph (80-100km/h) for approx. 1-1/2 to 5 minutes in 4th or 5th gear must be completed.

Trip Status Display
The "Trip status display" (display field 2) shows which components and/or systems have been checked since the drive started. After diagnostic of a particular component/system, the respective display value is set to "1" regardless if the diagnostic was recognized as OK or not OK. Because the components and/or systems are checked at each new engine start, the "trip status display" is reset to "0" at each engine start.

Readness Code Display
The "Readiness Code" (display field 1) shows whether the components and/or systems checked in display field 2 by the ECM were recognized as OK or not OK. If the diagnostic was recognized as OK, the respective display value in display field 1 is set to "0". If the diagnostic is not OK, the respective display value remains at "1". If each component and/or system has been operated at least once with a positive result, all the display values of the "Readiness Code" (display field 1) are set to "a" If a component or system is subsequently recognized as not OK in another diagnostic, the "Readiness Code" remains at "0" and is not set back to "1".

When resetting the "Readiness Code" if the "trip status display" is set to "1" but the corresponding display value of the "Readiness Code" is not set to "0", diagnostic was performed but not recognized as OK by the ECM. In this case, the DTC memory should be read for malfunctions (DTC's) or a selective diagnostic should be performed as follows:
- Read display groups 029, 030 and 038 during Three Way Catalytic Converter (TWC) diagnostic (banks 1 and 2).
- Read display group 024 during Evaporative Emissions (EVAP) system pressure diagnostic.
- Read display groups 007 and 008 during the Oxygen Sensor (O2S) control diagnostic.
- Read display groups 026, 027, 028, 035, 036 and 037 during O2S diagnostic.
- Read display group 034 during Heated Oxygen Sensor (HO2S) heating diagnostic.
- Read Display 017 during EGR system flow diagnostic.

DISPLAY OVERVIEW

VAG 1551 Display Overview, Display Group 023:

Readiness Code Display:

Interpreting The 5-Digit "Readiness Code"
Value "0" = Diagnostic performed (OK).
Value "1" = Diagnostic not performed or not OK.

Notes For Display Field 1:
^ All display values of the "Readiness Code" are set to "1" if the ECM connector is disconnected, the battery is disconnected, and/or every time the DTC memory is erased (either with address word 01, function 05 or with address word 33, mode 4).
^ To create the "Readiness Code" a "mixed city and highway" drive at 50 - 62 mph (80 - 100 km/h) for approx. 1-1/2 to 5 minutes in 4th or 5th gear with a preceding cold start must be completed.

Trip Status Display:

Interpreting The 7-Digit "Trip Status Display"
Value "0" = Diagnostic not yet performed.
Value "1" = Diagnostic performed.

Notes For Display Field 2:
^ All display values are set to "0" at each engine start so that the components and/or systems that influence exhaust emissions are always checked.
^ The EGR system is only tested for leaks after a prior cold start, Engine Coolant Temperature -10°C to 30°C (14-86°F).

Notes For Display Fields 3 and 4:
^ display field 4 evaluates the malfunctions "combustion misfiring" and "Oxygen Sensor control". display field 3 evaluates all other malfunctions.
^ If a malfunction is recognized, the corresponding counter is set to "40". The counter starts to count down after engine start-up when the drive is started with Engine Coolant Temperature (ECT) at 49°C (120°F). Counter stops when ECT is over 71°C (160°F). Counter counts down only if the Malfunction Indicator Lamp (MIL) is not on or no longer on. When the counter reaches "0", the recognized malfunction is erased.
^ If the DTC memory is erased, the counters are also reset.