PA cherokee club
It throws a camshaft position sensor code intermittently. But I recently replaced the camshaft position sensor. It also had a pending code that I had never seen. It said unknow diagnostic trouble code
CF Veteran
Joined: Dec 2009
Posts: 2,820
Likes: 3
From: Newport, pa
Year: 1997
Model: Cherokee
Engine: 4.0
Monitors may not at if dtc's are present... If/when the "unknown code" comes back, post up the code number.
☠ CF Sheriff ☠

Joined: Nov 2009
Posts: 15,197
Likes: 18
From: Aberdeen, MD
Year: 1995
Model: Cherokee
Engine: 4.0L HO I-6, 703 Injectors, Brown Dog Super Engine Mounts
this should help
NOTE: The monitor tests will NOT run if you have a check engine light
http://www.obd2.com/support/reprog/d..._procedure.pdf
http://repairpal.com/Drive-Cycle-Issues
I'm guessing the monitors that aren't ready are the EVAP and Catalyst...
There are specific criteria that tells the sensors when to cycle the tests. Based on what I have read make sure you do these things:
1) For the EVAP monitor - fuel tank between 1/4 and 3/4 full, gas cap tight and not leaking, let the vehicle sit for 8+ hours to start completely cold
2) For the catalyst monitor - The catalyst monitor will NOT run unless the Check Engine light is off, no fault codes are present, the fuel level is between 15 and 85 percent full, and the coolant temperature is above 70 degrees F. If these conditions have been met, the engine must have run at least 90 seconds, and the engine speed must be between 1,350 and 1,900 rpm. Idle vehicle for five minutes (to reach closed loop operation), the drive at a steady speed between 30 and 45 mph for two minutes. This test MAY NOT RUN until the EVAP monitor is "ready".
NOTE: The monitor tests will NOT run if you have a check engine light
http://www.obd2.com/support/reprog/d..._procedure.pdf
http://repairpal.com/Drive-Cycle-Issues
I'm guessing the monitors that aren't ready are the EVAP and Catalyst...
There are specific criteria that tells the sensors when to cycle the tests. Based on what I have read make sure you do these things:
1) For the EVAP monitor - fuel tank between 1/4 and 3/4 full, gas cap tight and not leaking, let the vehicle sit for 8+ hours to start completely cold
2) For the catalyst monitor - The catalyst monitor will NOT run unless the Check Engine light is off, no fault codes are present, the fuel level is between 15 and 85 percent full, and the coolant temperature is above 70 degrees F. If these conditions have been met, the engine must have run at least 90 seconds, and the engine speed must be between 1,350 and 1,900 rpm. Idle vehicle for five minutes (to reach closed loop operation), the drive at a steady speed between 30 and 45 mph for two minutes. This test MAY NOT RUN until the EVAP monitor is "ready".
this should help
NOTE: The monitor tests will NOT run if you have a check engine light
http://www.obd2.com/support/reprog/d..._procedure.pdf
http://repairpal.com/Drive-Cycle-Issues
I'm guessing the monitors that aren't ready are the EVAP and Catalyst...
There are specific criteria that tells the sensors when to cycle the tests. Based on what I have read make sure you do these things:
1) For the EVAP monitor - fuel tank between 1/4 and 3/4 full, gas cap tight and not leaking, let the vehicle sit for 8+ hours to start completely cold
2) For the catalyst monitor - The catalyst monitor will NOT run unless the Check Engine light is off, no fault codes are present, the fuel level is between 15 and 85 percent full, and the coolant temperature is above 70 degrees F. If these conditions have been met, the engine must have run at least 90 seconds, and the engine speed must be between 1,350 and 1,900 rpm. Idle vehicle for five minutes (to reach closed loop operation), the drive at a steady speed between 30 and 45 mph for two minutes. This test MAY NOT RUN until the EVAP monitor is "ready".
NOTE: The monitor tests will NOT run if you have a check engine light
http://www.obd2.com/support/reprog/d..._procedure.pdf
http://repairpal.com/Drive-Cycle-Issues
I'm guessing the monitors that aren't ready are the EVAP and Catalyst...
There are specific criteria that tells the sensors when to cycle the tests. Based on what I have read make sure you do these things:
1) For the EVAP monitor - fuel tank between 1/4 and 3/4 full, gas cap tight and not leaking, let the vehicle sit for 8+ hours to start completely cold
2) For the catalyst monitor - The catalyst monitor will NOT run unless the Check Engine light is off, no fault codes are present, the fuel level is between 15 and 85 percent full, and the coolant temperature is above 70 degrees F. If these conditions have been met, the engine must have run at least 90 seconds, and the engine speed must be between 1,350 and 1,900 rpm. Idle vehicle for five minutes (to reach closed loop operation), the drive at a steady speed between 30 and 45 mph for two minutes. This test MAY NOT RUN until the EVAP monitor is "ready".
Senior Member
Joined: May 2013
Posts: 734
Likes: 0
From: Shippensburg, PA
Year: 1999
Model: Cherokee
Engine: 4.0 I6
My buddy's blazer broke down on a hill near our friends house tonight in the snow. I strapped up and threw the jeep in 4 low and pulled it almost effortlessly up the hill. I was surprised cause he said he was even riding the brakes a little bit.
Got that jeep power.
Got that jeep power.
CF Veteran
Joined: Feb 2011
Posts: 1,212
Likes: 1
From: lewisberry PA
Year: 96
Model: Cherokee
Engine: 4.0
CF Veteran
Joined: Dec 2009
Posts: 2,820
Likes: 3
From: Newport, pa
Year: 1997
Model: Cherokee
Engine: 4.0


