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On-Board Diagnostics (OBD) Basics Diagnostic Services Introduction
Figure 4-1 Typical OBD-II Drive Cycle
As this is a generic drive cycle, it may have limited results on some vehicles. If available, use the
drive cycle information as supplied by the vehicle manufacturer.
System malfunctions that occur later and record a DTC (Diagnostic Trouble Code) will not change
the Readiness Test Status. When the failure is repaired and the DTC is erased, all Readiness Test
Status will be reset to a ‘Not Completed’ status.
Repair validation
Use the following procedure to validate a repair.
z To validate the repair:
1. Perform a drive cycle (generic or vehicle specific).
2. Check Service $03 (refer to Emission-related DTCs on page 14) and Service $07 (refer to
Emission-related DTCs detected during Current or Last Completed Drive Cycle (Pending
Codes) on page 22).
If no DTCs are reported (that relate to the initial failure), it can be assumed that the fault has been
repaired correctly.
4.3.2 MIL Status
Emission related malfunctions set failure specific DTC(s). The MIL (malfunction Indicator lamp)
may light up as soon as the first emission related DTC has been stored and confirmed (stored a
second time). Depending on the type of malfunction, it may take multiple drive cycles before the
MIL turns on.
Idle 2.5 Minutes
in Drive, A/C &
Rear Defrost ON
Cold Start
ECT < 50C
Accelerate at 50%
Throttle to 55 mph/
89 kph A/C OFF
3 Minutes
5 Minutes
Steady State Cruise
55 mph/89 kph
Decelerate to
20 mph/32 kph
with the Clutch
Engaged and
No Brakes
Accelerate at
75% Throttle to
55 to 60 mph/
89 to 97 kph
Steady State Cruise
55 to 60 mph/
89 to 97 kph
Decelerate to
End of Cycle
Without Brakes
HO2 Heater, Misfire,
AIR, Fuel Trim, and
Purge Monitors
Misfire, Fuel Trim, and
Purge Monitors
Misfire, EGR, AIR, Fuel Trim,
HO2, and Purge Monitors
EGR, Fuel Trim, and
Purge Monitors
Misfire, Fuel Trim, and
Purge Monitors
Catalyst, Misfire, EGR, Fuel
Trim, HO2, and Purge Monitors
EGR, and Purge Monitors
Total Time 12 Minutes
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