Since it is only letting you know that something is wrong with the EVAP system, it is almost always accompanied by It often appears with, or is related other codes, such as: P0440: Evaporative Emission Control System Malfunction It does not allude to what that problem might be. P0440 Indicates that something is wrong with the EVAP system. This trouble code references a number that is given to you when you plug your Grand Cherokee into a OBDII scanner. Equipment attached to the vehicle will be able to tell if the computer is in its readiness mode and will fail it until it is ready and the MIL remains out.A very common trouble code with the Jeep Grand Cherokee is the P0440 code. Clearing the codes to fool emissions testing will not work. It is at this point where the computer will re-trip the MIL if it detects the repair was not made to the Grand Cherokee. This may take several normal driving cycles for the computer to communicate with all the sensors and circuits until it is in readiness mode.
It will relearn and recommunicate with all the sensors and circuits integrated to the system.
While they can be reprogrammed, obtaining the information will have to come from a Jeep dealership and will incur cost. Once the memory of the computer is wiped out, the vehicle will go into protection mode and also wipe out the radio and internal alarm systems, making them both inoperable. Most all newer vehicles come with theft-prevention radios and internal alarm systems. While you can erase codes on OBD II Grand Cherokees by following Section 2 without using a scanner, it is not recommended on later models.