We understand your Jeep Cherokee (5 Speed) is having difficulty getting certain emission monitors to complete (become Ready). The emission monitors are programmed to run while your Jeep is being normally operated. However, due to different driving habits, the criteria required to run a monitor may not always be met. Following the Jeep Cherokee drive cycle below should allow all emission monitors to complete. The drive cycle must be followed accurately. Take extra caution when performing the drive cycle on public roadways. Perform the drive cycle at your own risk. Perform the drive cycle safely and obey all traffic laws.
We're going to recommend that you follow the drive cycle below at least twice, and if after that your Cherokee still has not completed (made ready) all the emission monitors required to pass the smog inspection, seek the assistance of a smog check repair station which will be able to perform the drive cycle on a dynamometer and be utilizing specialized OBD II drive cycle readiness tools/scanner/computer. Mode 6 (emissions diagnostics tool) is especially helpful when trying to complete emission monitors. A well trained smog technician will be able to use Mode 6 to manually run emission monitors.
How to Perform a Jeep Cherokee (5 Speed) Drive Cycle
The Jeep Cherokee drive cycle below will complete or make ready your vehicle's emission monitors, including the EVAP monitor, Oxygen Sensor monitor, EGR monitor, Secondary Air Injection, and Catalyst monitor. If after completing the drive cycle your vehicle will still not complete any or all the monitor(s) we have to recommend visiting a Jeep dealer or the smog check repair center.
We should note, the secondary air injection monitor which checks for the performance of the air injection system and air injection pump requires the monitor run during a cold (engine) start. Once the engine warms up, the monitor is done checking the air injection pump and will continue on checking the performance of the remainder of the AIR injection system. With that said, it's not the number of miles driven which resets the air injection monitor, rather the number of cold starts required to get all the other parameters required for the air injection monitor to to run. Starting the engine after the vehicle has sat for at least 8 hours in normal weather conditions would be considered a "Cold Start". Since the air injection monitor takes into effect ambient air temperature, it is best to perform a cold start on a morning.
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A. Cold Start - In order to be classified as a cold start the engine coolant temperature must be below 122°F and within 11°F of the ambient air temperature at startup. Do not leave the key ON prior to the cold start or the heated oxygen sensor monitor may not run.
B. Idle - The engine must be run for two and a half minutes with the air conditioner and rear defroster on. This will test the O2 heater, Passive Air, Purge "No Flow", Misfire. If the engine has achieved closed loop condition, the Fuel Trim test will run as well.
C. Accelerate - Turn off the air conditioner and all the other engine loads, (e.g. lights, stereo) and apply half throttle until 55mph is reached. During this time the Misfire, Fuel Trim, and Purge Flow tests will be performed.
D. Hold Steady Speed - Hold a steady speed of 55mph for 3 minutes. During this time the Oxygen Sensor response, Air Injection System, EGR, Purge, Misfire, and Fuel Trim tests will be performed.
E. Decelerate - Let off the accelerator pedal. Do not shift, touch the brake or clutch. It is important to let the vehicle coast along gradually slowing down to 20 mph. During this time the EGR, Purge and Fuel Trim tests will be performed.
F. Accelerate - Accelerate at 3/4 throttle until 55- 60mph speed is achieved. This will perform the same diagnostics as in step C.
G. Hold Steady Speed - Hold a steady speed of 55mph for five minutes. During this time, in addition to the diagnostics performed in step D, the catalyst monitor (catalytic converter) diagnostics will be performed. If the catalyst is marginal or the battery has been disconnected, it may take 5 complete driving cycles to determine the state of the catalyst. This is important to note especially for an older model vehicle, or for one with over 100,000 miles.
F. Decelerate - This will perform the same diagnostics as in step E. Once again, don't press the clutch, brakes or shift gears.
Following the Jeep Cherokee drive cycle above should allow all emission monitors to complete. The drive cycle must be followed accurately. Once again, take extra caution when performing the drive cycle on public roadways and perform the drive cycle at your own risk. Drive your vehicle safely and obey all traffic laws.
