Emissions - OBD-II Readiness Test Drive Cycle: Overview
Group36 - Engine Electrical
Number
02-36-029
Date
12-2002
Model
Accent 1996-1999
Subject
OBD-II Readiness Test Drive Cycle For 1996-1999 Accent
DESCRIPTION:
This TSB describes Drive Cycles which may assist the vehicle's OBD-II system to complete the necessary emissions systems tests and set the OBD-II Readiness Monitors to display READY (or COMPLETED -- described simply as "READY" in this TSB). This TSB specifically covers the 1996-1999 Accent.
The drive cycles described below are specifically designed to set the following items:
^ CATALYST
^ EVAP.PURGE
^ 02 SENSOR
^ 02 SENSOR HEATER
READINESS MONITOR:
The readiness monitors indicate if all the necessary emissions systems tests have been completed by the ECM.
This feature is a part of the OBD-II system.
It ensures that vehicles have had sufficient time to conduct all necessary emissions related diagnostics:
^ after a repair which resulted in the power to the ECM being interrupted
^ or resulted in clearing of Diagnostic Trouble Codes (DTCs) using a scan tool.
REPAIR PROCEDURE:
Depending on the model year of the vehicle, follow the correct Drive Cycle pattern.
IMPORTANT
In order to set the Readiness Monitors to READY, the vehicle must successfully complete the appropriate Drive Cycle TWO TIMES.
DEFINITION OF TWO CONSECUTIVE DRIVE CYCLES:
That is, the vehicle must:
1. Complete the Drive Cycle.
2. The ignition key must be turned to the OFF position and stay off for at least 30 seconds.
3. Complete the Drive Cycle a second time.
IMPORTANT
The two Drive Cycles MUST be completed on two CONSECUTIVE drives. CONSECUTIVE means that the two success. OBD-II Readiness Drive Cycles cannot be interrupted by any other kind of driving between them.
WARNING:
PRE-EXISTING CONDITIONS ON THE VEHICLE:
The vehicle will not set the Readiness Monitors even if the Drive Cycles are performed correctly, if the vehicle has certain pre-existing conditions.
Such as:
^ Stuck Open Thermostat: If the thermostat is stuck open, the Engine Coolant Temperature (ECT) reading may drop below 176 degrees F. If the ECT reading drops below 176 F (especially during the steady state highway driving where the airflow across the radiator will cool the coolant quickly), the Drive Cycle will NOT be effective. In order for the Drive Cycle to "count," the ECT reading must be above 176 F.
^ Radiator Fans Stuck ON: If the radiator fans are stuck ON, the ECT reading may drop below 176 F during the Drive Cycle. As with the stuck open thermostat, this condition with negate the Drive Cycle.
ROAD CONDITIONS:
The type of road that the Drive Cycle is performed on is important.
The BEST type of road for performing the Drive Cycle is one that is as Level (Flat) as possible.
If the Drive Cycle is performed in an area with hilly terrain, it will be more difficult to successfully perform the Drive Cycle. In this case, it may require that the Drive Cycle be performed more than two times to ensure success.
DRIVE CYCLES IN THIS TSB:
There are four (4) different Drive Cycles included in this TSB, depending on the Model Year and Specifications of the Accent.