To get a list of Jeep Grand Cherokee fault codes, look online at websites such as WJjeeps.com or Engine-Light-Help.com. To access the fault codes on a Jeep Grand Cherokee, use an OBD II scan tool.
To retrieve the Jeep check engine fault codes with the OBD II scan tool, connect the tool to the 16-pin connector, which is near the vehicle's steering column. This connector may have a cover that is removable. Turn on the ignition, and then follow the operating instructions for the scan tool to access the codes. The codes are manufacturer specific, so make sure to use the appropriate resource to look them up.
The diagnostic trouble codes that appear indicate that the powertrain control module recognizes that there are an abnormalities in the vehicle's system. The codes show that there are failures, but they do not necessarily identify the exact components that are failing.
Each code starts with the letter "P," and a series of numbers follow. The P indicates that the vehicle has a powertrain mechanism, and the second number indicates either a standard or manufacturer-specific issue. The third digit shows what system the issue is affecting; an example is P1390, which shows that the issue with the car is that the timing belt is skipping one or more teeth.