1996 grand cherokee ATC fault code 40 blow out floor only
07-11-2011, 10:42 PM
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Model: Cherokee
1996 grand cherokee ATC fault code 40 blow out floor only
I have a 1996 jeep cherokee 4x4 Grand zj limited and I am getting air blow at the floor vents only. After puttint the ATC display in diagnostic mode I get a code 40. I have looked at the linkage under the dash and even the linkage that goes from driver to mid lower dash and it seems to be working with no broken parts. I have looked over the vac hoses around engine and didnt see any holes or any hanging off. I found this online Historical Fault Codes:40......... circuit was shorted..........................Mode Door Feedback Circuit and this in my haynes manual 40......feedback was to high.............blower/fan feedback circut. I do not know how to reed the codes here. 
07-12-2011, 08:39 AM
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Year: 2011
Model: Grand Cherokee
Engine: 5.7
does the haynes manual tell u how to enter circuit diagnostics? if not, i can email you the section from the repair manual...
07-12-2011, 02:24 PM
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Year: 2011
Model: Grand Cherokee
Engine: 5.7
My book says code 40 is Feedback was too high in the Blower/Fan feedback circuit.
ONce in diagnostic mode, turn the dial till 02 shows up, then push the AC button. That will give you the value the controller received. Should be between 00-255. "?" for unknown value, "OC" for open circuit, "SC" for shorted circuit.
ONce in diagnostic mode, turn the dial till 02 shows up, then push the AC button. That will give you the value the controller received. Should be between 00-255. "?" for unknown value, "OC" for open circuit, "SC" for shorted circuit.
06-21-2018, 06:36 PM
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Model: Cherokee (XJ)
I have the same
My book says code 40 is Feedback was too high in the Blower/Fan feedback circuit.
ONce in diagnostic mode, turn the dial till 02 shows up, then push the AC button. That will give you the value the controller received. Should be between 00-255. "?" for unknown value, "OC" for open circuit, "SC" for shorted circuit.
ONce in diagnostic mode, turn the dial till 02 shows up, then push the AC button. That will give you the value the controller received. Should be between 00-255. "?" for unknown value, "OC" for open circuit, "SC" for shorted circuit.
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