Readiness Test Status

SYSTEM READINESS TEST STATUS

PURPOSE
The Readiness function (also referred to as I/M Readiness or I/M Flags) indicates if a full diagnostic check has been "Completed" (is "Ready") for each non-continuous monitor. Enhanced I/M State Emission Programs will use the Readiness status (Codes) to see if the vehicle is ready for OBD-II testing. "Incomplete" (Not Ready) codes will be one of the triggers for I/M failure.

OVERVIEW
The PCM monitors the following main diagnosis items and records whether the evaluation was completed or is incomplete. The Readiness codes were established for the I/M programs, thereby confirming that the vehicle was not tampered with by erasing the diagnostic trouble code(s) (DTCs) before I/M testing. The Readiness and DTC codes can be reset by disconnecting the battery or by erasing the codes with a scan tool. For this reason all Readiness codes must read "Complete" before I/M testing.

When the monitors run and complete, the scan tool MB991958 (MUT-III sub assembly) will record the Readiness Code as "Complete" (General Scan Tools record as "Ready"). When the vehicle is operating normally and the OBD-II Drive Cycle is carried out, Readiness Code will set as "Complete" on the first drive cycle. If during the first drive cycle a fault is detected then, a second drive is required before the Readiness Code will "Complete" If the fault is still there, then a DTC will set
- Catalyst: P0421, P0431
- Evaporative system: P0442, P0455, P0456
- Heated oxygen sensor: P0130, P0131, P0132, P0133, P0134, P0136, P0137, P0138, P0139, P0150, P0151, P0152, P0153, P0154, P0156, P0157, P0158, P0159
- Heated oxygen sensor heater: P0135, P0141, P0155, P0161
- EGR system: P0401

After the Readiness is "Complete," the technician is assured that any DTCs associated with that monitor will be displayed if the system has a problem. That is why some State's I/M programs require the Readiness Code as "Complete" before they check for DTCs.

NOTE: After a repair is for a DTC the technician should drive the OBD-II drive cycle checking that the scan tool MB991958 (MUT-III sub assembly) records all Readiness as "Complete".