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2008 grand cherokee limited 5.7 l

939 views 9 replies 5 participants last post by  90grandoneer 
#1 · (Edited)
check engine light wont go off changed sensors cats updated computer still slow response time anyone else have this problem please help
 
#2 ·
There are members looking at your post but the scant information you gave us won't get you much of a response. What code?, which sensors? Slow response in what way? And I'm not sure what a FSJ Cherokee is.
 
#4 ·
X2 on the info. Dick, the FSJ is Full Size Jeep, like my old 90 Grand Waggie.
 
#3 ·
pent00,

I'm sorry to hear about your concern. How long has your check engine light been on? Is it intermittent, or has it remained on for an extended period of time?

Below is what can be found in the owner's manual in regards to the Malfunction Indicator Light.

"This light is part of an onboard diagnostic system called OBD II that monitors engine and automatic transmission control systems. The light will illuminate when the key is in the ON position before engine start. If the bulb does not come on when turning the key from OFF to ON, have the condition checked promptly.

Certain conditions such as a loose or missing gas cap, poor fuel quality, etc. may illuminate the light after engine start. The vehicle should be serviced if the light stays on through several of your typical driving cycles. In most situations the vehicle will drive normally and will not require towing.

The Malfunction Indicator Light flashes to alert you to serious conditions that could lead to immediate loss of power or severe catalytic converter damage. The vehicle should be serviced as soon as possible if this occurs."
 
#6 ·
i changed the o2 sensores multaple times new cats map sensore computer update the light has been on for the most part of a year codes always have to do with o2 sensores not sure the exact codes but the most recsent was slow responce time bank 2
 
#7 ·
I have a some questions that my help us try to figure out your problem(s):
1. Is your fuel economy worse than normal for a Hemi.....~13-14 mpg in town, ~14-15 mpg mixed, and ~16-18 mpg highway?
2. Has anyone checked the fuel trims, both long and short term? If so, what are they (+/- number ranges)? This may give you a big clue as to what could be happening, at least with the O2's.
3. If your fuel economy is bad, have you checked for exhaust leaks? Depending how bad they are, you could get all kinds of erroneous codes as the PCM tries to compensate for the leaks.
4. Has anyone checked the wiring integrity from the PCM to the affected sensor(s)? Also the plugs at the O2's?
5. Has anyone done a computerized diagnostic test of the PCM functions? Programming updates won't help if there is an electronic glitch in the PCM.
6. What brand O2 Sensors have you been installing?
7. What is/are the DTC code(s) you have been receiving? We need the actual letters/numbers here.
8. Has anyone had a computerized diagnostic scanner hooked up to it when the code(s) is/are triggered? When this happens you can pull up "live data" on the tool and see exactly what was going on with all engine management systems just before the code was set.
 
#10 ·
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