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Display Group 029





Display group 029 (Diagnostic status)

NOTE: OBD II regulations require a display ("Readiness Code") that indicates readiness for inspection (annual exhaust emissions test). The readiness code display (display field 1) shows that every component and/or system that affects the exhaust, which can lead to switching on the MIL, has been operated at least once with positive result.

The readiness code is reset and/or erased:
- Every time the DTC memory is erased (both with address word 01 function 05 and with address 33 mode 4).
- When the battery is disconnected.
- When the ECM is disconnected (e.g. connecting test box VAG 1598/19, replacing ECM, etc.).

To generate the readiness code, take a "mixed city and highway" drive (short test). A "mixed city and highway" drive is understood to be approx. 1-1/2 to 5 minutes at 80-100 km/h (50-63mph) with manual transmission in 4th or 5th gear, or automatic transmission selector lever in "D" position, preferably in 4th gear.

The "Trip Status" display (display field 2) shows which components and/or systems have been checked since the start of the trip. After successful diagnosis, the current display value is set to "1" whether the diagnosis was recognized as OK or not OK. The trip-status display is reset to "0" at each start since the components and/or systems are checked at each new start. A "trip" is understood to be a drive of approx. 1-1/2 to 5 minutes at 80-100 km/h (50-63mph) with manual transmission in 4th or 5th gear, or automatic transmission selector lever in "0" position. preferably in 4th gear, with preceding cold start.

The readiness code display (display field 1) shows whether the components and/or systems checked in display field 2 were recognized as OK or not OK by the ECM.
- If the diagnosis is recognized as OK, the current display value is set to "0."
- If the diagnosis is recognized as not OK, the current display value is not set to "0", it stays at "1."
- If every component and/or system has operated at least once with positive results, all display values of the readiness code are set to "0."
- If, during another diagnosis, a component and/or system is recognized as not OK, the readiness code is not reset to "1."

If the trip status display is set to "1" when the readiness code is regenerated, but the corresponding display value of the readiness code is not set to "0", the diagnosis was carried out but recognized as not OK by the ECM. In this case, the DTC memory should be checked to determine malfunctions and/or to carry out a selective diagnosis:
- For three way catalytic converter diagnosis (Bank 1 and 2) also check display groups 035, 036 and 044.
- For the Secondary Air Injection (AIR) system throughput and leak diagnosis, also check display groups 020 and 021.
- For oxygen sensor diagnosis, also check display groups 032, 033, 034, 041, 042 and 043.
- For oxygen sensor heating diagnosis, also check display group 04a
- For the Exhaust Gas Recirculation (EGR) system throughput diagnosis, also check display group 017.
- For the Evaporative Emissions (EVAP) system leak diagnosis, also check display group 045.






Notes on display field 1:
- All readiness code values are set to "1" by disconnecting the ECM harness connector and/or disconnecting the battery, and every time DTC memory is erased (both with address word 01 function 05 and with address word 33 mode 4).
- To regenerate the readiness code, take a drive of approx. 1-1/2 to 5 minutes at 80-100 km/h (50-63mph) with manual transmission in 4th or 5th gear, or automatic transmission selector lever in "D" position, preferably in 4th gear ("mixed city and highway" trip).
- Value "0" = Diagnosis carried out
- Value "1" = Diagnosis not OK and/or diagnosis not carried out yet





Notes on display field 2:
- The display values are set to "0" at each start, since the function capability of components and systems that can affect the exhaust are checked again and again.
- Leak testing of the EGR system is only carried out after a preceding cold start (water temperature -10°C to 30°C (14° to 86°F).
- Value "0" = Diagnosis not carried out yet
- Value "1" = Diagnosis carried out

Notes on display fields 3 and 4:
- Display field 3 evaluates all malfunctions except "Combustion misfiring and oxygen sensor control."
- Display field 4 evaluates only the malfunctions "Combustion misfiring and oxygen sensor control"
- If a malfunction is recognized, the corresponding counter will be set to "40." The counter is decremented, during a new start, when the trip was started at coolant temperature of 49°C (120°F) and ended at an engine coolant temperature of 71°C (160°F) and the malfunction is no longer recognized. However, decrementing is only allowed If the MIL has not lit up yet or is no longer lit. When counter status "0" is reached, the recognized malfunction is erased.

- If the DTC memory is erased, the counter is also decremented.
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