The battery is only 1 1/2 years old, the test says that with engine on, 14.57 volts, where it should be. I'm guessing the code was triggered by a cold start on a cold morning. Anyone have any other ideas? Thank you!


I think I found (and cleared) the problem...14.57 volts means the alternator is working properly, I tested the battery and it's 12.6 volts (perfect), the leads don't have any corrosion, all the wiring looks solid. I disconnected the negative cable to the battery for 30 minutes, reconnect, and started the engine. No more code! Sometimes the computers can be fooled into throwing false codes.

If any one cares to know, P0562 is an undervolt error meaning the the electrical system read less than 10 volts for more than 60 seconds.

Sometimes starting a cold Jeep on a cold morning without using the engine heater can trigger a false undervolt warning. I've been through this before. What I did NOT know was disconnecting the battery for more than 30 minutes would reset the computer. A result, the evaporative sensor AND the O2 sensor needed to be used (meaning driving around, both streets and highway) BEFORE they were ready to take an emissions test. The only solution (recommended by both the manual and the emissions testing site) was to drive around for a week. It worked, but I had to burn a tank of gas before the Jeep was ready.

To see if your Jeep is ready to take an emissions test, use the key and JUST turn on the electrical power (not the engine), and stare at the dashboard....look at the "check engine" light for 15 seconds, and it stays a solid light...then it is good to go. But....after 15 seconds if the "check engine" light starts blinking for 10 seconds, then nope!