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How to complete the Drive Cycle for Jeep Cherokee XJ

Credit to Smogtips.com

 

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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.