Hi,
I have a 2002 Jeep Grand Cherokee Laredo. Lately, the check engine light has been coming on. I ran a diagnostic test (ignition on/off on/off on/off on) and it shows the codes P 0122, P 0456. I was able to find info on P 0456 (possibly a bad seal on gas cap - gonna check it out), but I haven't been able to find anything regarding P 0122. Can anyone offer any information as to what this is, and what might cause it. Also, any fix information would be greatly appreciated. Thanks!
Matt
Matt,
Reference the factory manual for 2000 (should be very similar).
P0122 - Throttle position sensor input below the acceptable voltage range, or APPS voltage input below the minimum acceptable voltage.
P0456 - Leak has been detected in the evaporative system.
Russ
P0456 is small leak detected. There are three leak fault codes. Small, medium P0442, and large P0455. Small leak is the tech's most dreaded fault [other than multiple cylinder misfire :) ] It could be the vacuum valve in the gas cap. They can accumulate trash and some rust and leak.
Bill
Russ had already covered that one...
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