Hello from the Pacific Northwest USA,

Yesterday I parked my 02 XJR for 15 minutes after sitting in traffic for about 25 minutes. My car has 66,000 miles. I have never serviced the transmission. It was about 80 degrees outside.

I went to start it and it just cranked and cranked. I got two messages with the amber warning light: "Trans too Hot" and "Fail-safe mode" (or something like it). I left the ignition on and put the gear selector in drive and then back in park. It started and all the warning lights went out. The engine temperature was normal.

I drove to the mechanic (he's good but not a Jag mechanic) to see if he would get any codes. The only code he got was "P1260 Security input theft detected, immobilized. Theft detected - engine disabled." He suggested I change the battery in my key fob, which I did. I had no other starting problems the rest of the day and no warning lights.

Should I flush my transmission? Of course, I don't want to service the transmission if it's not needed, but the last thing I want is a transmission problem that could be avoided with new fluid.

I've had this car about a year and a half and have come to totally rely on it. It really is an amazing car and has been reliable. It always starts right up and never throws any codes. I don't want to feel nervous every time I try to start it.

Any thoughts would be greatly appreciated!

 

change this and the ATF

 

2007 XJ8 VDP 39000K is now doing the same thing except it won't even turn over but starts fine after a 15/20 minute wait. What does the battery in the key fob have to do with the car cranking?

 

Thank you for the suggestion. What does that transmission part do? I see the part on Amazon is $130. Do you have an idea how much the labor would be to do the work?

 

In my case, my mechanic suggested changing the battery in the key fob because my car had an error code that meant the car thought there was an attempted theft and the engine was disabled. So he guessed a weak battery, which is cheap to replace, may, however unlikely, be the cause of the car failing to start. But that doesn't explain the warning messages of the transmission being too hot and the car being in fail-safe mode. For $5 I replaced the batteries in both my key fobs. They were probably ready to be replaced anyway so I didn't mind doing it.

 

Failure of that conductor plate is very rare. Forget it unless you can find
a post that directly implicates the part in your particular circumstances.

Change, don't flush the transmission fluid. Change the connector bushing at
the front right corner of the transmission. It is a known leak point.

I've had that message a couple of times, always after a wet drive. I take
it that there is some damp sensitive wiring somewhere. It always resolves
after a restart.

 

I have permanently fixed the issue, I cant say for others.

it isn't much bigger job than a ATF change. 2 hours of lab is the max otherwise your shop is ripping you off.

 

Hi plums,

Can you please elaborate on the reason for changing but not flushing the transmission fluid? Any concerns about mixing different fluid types?

Thanks,

Don

 

I had my fluid and filter changed last week. It might be my imagination, but I think it's shifting smoother than before. So far, no warning lights have come on. The car seems as good as new. Keeping my fingers crossed that has solved my problem. Thanks again to Vincent and Plums for your suggestions!

 

I had the exact same thing happened to me about a month ago. It was dead the morning I had to go to work with. I had done a complete tranny oil/ filter/ electrical conductor plate/ tranny harness connector change a couple of months before the problem showed up and wondered if the cause was what I might have did wrong. When the problem showed up, I checked the tranny harness connector of oil leaks (none), tranny harness to tranny module connector to see if oil wicked up to the module (none), and the last thing I did was to charge the battery to above 13.0 volts. I drove it around a few days and then it happened again one morning. "Transmission High Temperature" and "Fail-Safe Mode" showed up. Oddly, the message went away when I shifted to park or neutral. It will come back on with all other gears. It ran roughly. I said to hell with it and drove it. A block away later the messages went away, car drove fine and it never came back. It has been a month later and still no message. I still do not know the cause of the problem and still perplexed....

 

I should have said "back flush".

I forward flush through the hoses by cranking the motor without starting.

No concern about mixing ATF. For the records, on the W5A580 MERC transmission
I use Valvoline Maxlife Dex/Merc. Cheap as chips.

 

Yes, but wasn't your car flooded up to the axles at one point?

 

The temperature is not read unless in gear.

It's a documented "feature" of that transmission/TCM combination.