Readiness Codes

Readiness Codes

OBD-II systems are required to generate a report concerning the operational status of up to 8 emission functions. This report is called the readiness code, and is viewable on both the generic scan tool and the VAG 1551/1552 and VAS 5051 scan tools.

The readiness code indicates whether a particular system or function passed the appropriate operational test and was found to be within specification (for the duration of the test). Malfunctions in the system that occur later and record a DTC will not change the readiness code. However, when the fault is repaired and the DTC is erased, the readiness will also be erased.

Accessing the OBD-II system with a scan tool allows access to data that can indicate if:
^ a readiness code test is running
^ there is a fault
^ there is no fault

If the readiness code indicates that the diagnostics nave not been performed, several methods can be used to confirm the required operation and set the codes.

Readiness codes can be useful for several reasons:
^ During an emissions test, the readiness code can be used to confirm system function and may be required in some geographical areas.
^ After emissions system repairs, proper operation can be confirmed by using the readiness code.

Setting readiness codes

Several methods exist for setting readiness codes. Some methods will not work with some systems, so the appropriate VESIS repair information must he consulted for the correct procedure.




The first method of setting the readiness code is by driving the vehicle in a prescribed manner called the Federal Test Procedure 72 (FTP72) driving cycle. This procedure, as shown in the accompanying illustration, requires that the vehicle be driven 75 miles (12.07 KM) over a period of 1372 seconds (22 minutes, 52 seconds) at a maximum speed of 56.67 m.p.h. (91.2 kph) from a cold start. This procedure allows all of the diagnostic procedures to run and if completed successfully, the readiness code will set. Carrying out this procedure can be difficult due to the time factor involved and the need for a cold start.




The second method for setting readiness codes involves the use of scan tools VAG 1551/1552 or VAS 5051. In this instance, a road test, or "short trip," is used with the scan tool overriding some of the normal ECM programming to force diagnostics to run. This procedure is run following VESIS procedures specific for each vehicle and system. It considerably shortens the time required to set the readiness code.

The newest method of setting readiness codes allows the technician to use the appropriate scan tool, and set the code without the need to drive the vehicle. This procedure can only be used on the newer engine management systems where it has been programmed into the ECM. Specific VESIS procedures must be followed for each individual version.