2001 Jaguar S type 4 liter 53k miles. My wife was driving the Jag and it just stalled in the middle of the street. The car would nor restart so I had it towed to my house and after some investigation notice that the LED light was blinking and as I remember the blinking of about 13 times which led me to the PATS (Passive Antitheft system) had disabled the fuel pump. Jags are sensitive to battery so as a precaution I replace the battery. I was able to get the PATS light to stop blinking by locking the car with a remote and then holding down the remote unlock button until all the doors unlocked and the windows rolled down and the sun roof opened. I then held the lock button until everything locked again the windows and sunroof closed. After that the LED PATS light acted normal and I was able to start the car. I checked for codes and found U1262 and U17FF. I don't want my wife driving the car with these codes even though it's now drivable. The research I have done indicates that there is a communication problem with either a ground or a loose missing connection to a module. I'm looking for some guidance as to where to start looking either one of the grounds you may recommend or one of the modules that may have a wiring problem. Also if you have a procedure to trouble shoot the PATS It would help.
Thanks for you help
Howard

 

After any repair clear all codes. Then drive the car and see what returns. Sounds like you found the problem (Battery) and changed it.
Report back and let us know if that worked.

U codes are network codes and will be very common with any low voltage situation which your car had with the battery problem. I never worry about those until all battery issues have been solved. If your an IT guy think about it like an event log on a computer. It tells you what happened in the past and while that is a help to solving things the current status is what's most important.

It would be helpful if you can measure the battery voltage of the car after it has set all night. 12.6 is a minimum value to look for.
But I would first just clear the codes as I bet they won't come back.
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In addition, charge that poor battery to be safe. Most new batteries are not fully charged at time of sale. Don't rely on the alternator alone to bring up the charge.

Also, check your car's charging system to make sure it didn't lead to an early demise of the old battery. Measure the voltage directly on the battery posts. On an early model, engine at idle, you should see approximately 13.7V. If too low, the battery won't get a proper charge. Too high can cook a battery, reducing its ability to accept or hold a charge.

 

Thank you. When the weather gets better in Michigan I will take it for a long drive to see if the codes reappear.

Howard

 

Thank you. I will definitely check the charging voltage at idle.
Howard