Readiness Code: Notes

The readiness code provides status (Yes/No) of the system having completed all the required monitoring functions or not. The readiness code is displayed with an aftermarket Scan Tool or the DISplus/MoDIC . The code is a binary (1/0) indicating;

0 = Test Not Completed or Not Applicable - six cylinder vehicles (not ready - V8 and V12)
1 = Test Completed - six cylinder vehicles (ready - V8 and V12)

A "readiness code" must be stored after any clearing of fault memory or disconnection of the ECM. A readiness code of "0" will be stored (see below) after a complete diagnostic check of all components/systems, that can turn on the "Malfunction Indicator Light" is performed.

The readiness code was established to prevent anyone with an emissions related fault and a "Malfunction Indicator Light" on from disconnecting the battery or clearing the fault memory to manipulate the results of the emissions test procedure (IM 240).

Interpretation of the Readiness Code by the ECM(s) (SAE J1979)

The complete readiness code is equal to "one" byte (eight bits). Every bit represents one complete test and is displayed by the scan tool, as required by CARB/EPA. For example:

0 = EGR Monitoring (=0, N/A with BMW)

1 = Oxygen Sensor Heater Monitoring

1 = Oxygen Sensor Monitoring

0 = Air Condition (=0, N/A with BMW)

1 = Secondary Air Delivery Monitoring

1 = Evaporative System Monitoring

0 = Catalyst Heating

1 = Catalyst Efficiency Monitoring

Fig 1: Identifying Secondary Air Delivery Monitoring

Courtesy of BMW OF NORTH AMERICA, INC.

Drive the car in such a manner that all tests listed above can be completed (refer to the DRIVE CYCLE ). When the complete "readiness code" equals "1" (ready) then all tests have been completed and the system has established its "readiness".