And only yesterday I was a newbie, I have a feeling this car will have me on this site as much as the Lincoln had me on LincolnVsCadillac :-)

So my situation today was this. I took a short ride to the store after work and all was fine, still monitoring fuel trims for my other issue so I had my code reader still in car (I did unplug when I went into store). I was in the store about 45 minutes and came out and started the car and all was fine. Using the code reader I decide to look around in the OEM section (I previously only look in the generic section of codes. As soon as reader downloaded the DTCs in this Jaguar specific the dash beeped and the DTCs showed:
A Generator Fault (P1632 I think),
P1642 displayed
MIL light came on
Traction Control light came on,
Cruise Control unavailable message
DSC unavailable message
battery light was on
gear fault message
Temperature gauge went to zero
Tachometer went to zero (but car was still running)
Gear shift was locked in park
Parking brake failure warning

I was a bit freaked out but being the good IT guy that I am I decided to just reboot it, same thing upon a restart so I thought I wasn't going to be able to drive home and was a bit worried about my frozen shrimp. Upon restarting I noticed that the tach was working for the first 10 seconds so I quickly put the car in reverse during this 10 second grace period. Now that car was driving I limped it home (very appropriately named mode as I really did feel like I was limping home). I really assumed it was a bad alternator so I expected the car not to make it home but it did. After getting home I got my multimeter and when I came back and restarted car, all messages were gone except the MIL. Battery voltage with car running was a bit lower than I expected until I read up on the charging circuit and found out there were 2 voltages alternator could put out (13.? and 14.?).

Took the car for a ride and all seems fine again (and happily my long term trims continue to move slightly lower).

I've done a ton of reading here on the site and realize that these cars are very sensitive to low voltage situations so I suspect that this was the result of the voltage not quite being high enough at startup. I always heard that the Lincoln LS (my previous ride) was like this too although I never saw any similar issue.

One more thing I should mention is the battery was replaced in June as I had the car parked for a couple years and the old one was quite done.

I guess all I am asking is:
1. Are my symptoms what I've seen called "Limp Home Mode" If so, what is the point of locking the gear shift lever.
2. Should I worry about this or just watch it. I only work about 10 miles from home and have AAA so breaking down isn't a huge showstopper for me
3. Is the CAN link failure code typical of a low voltage situation?
4. Is it still true that aftermarket batteries will always show the battery light? I see Rock Auto has an ACDELCO made by Nippondenso, would that be comparable to OEM?
5. Can I somehow force the higher voltage from Alternator, the 13.3v I got from the battery when running seems low to me but maybe that is the low power mode

I did read through this thread as well as a few more where almost every answer was battery :-)
https://www.jaguarforums.com/forum/s...oltage-179828/

133k on the car

 

limp mode.... haha, that's what she said.....

 

Limp mode etc do not lock the gear shift so you're looking at a cause for that - but everything else points to a low battery, whether due to your short journeys, some drain as yet unsuspected, a bad battery despite being newish, bad connection or whatever.

Some main causes of gearshift lock:
1. loose/absent bolt(s) where its cable is fixed to the side of the trans - check the 2 8mm hex bolts from under the car
2. failed/failing brake micro switch
3. failed/failing interlock inside the J-gate

You can't easily if at all command a higher charging voltage and anyway should never have to. The PCM is good at this so if it's not doing the right thing it may be a sign of a bad connection or something.

I don't know the voltages fro your car but they are likely in the workshop manual (as for my car).

If you routinely do short journeys you might want to get one of the fancy modern battery maintainers such as made by ctek.

 

+1 on that. With so much happening all at once, there's likely one common cause: low voltage.

As smart as these cars can be, they are also very dumb about warning us of certain faults in a timely manner. I'd suggest giving the charging system a good once over. As JagV8 mentioned, there are many possible reasons to end up with low battery voltage. Don't just load the parts catapult, but properly diagnose the system first. A very likely cause is short, infrequent trips with high electrical loads.

Switching to all caps to make sure I have your attention:

ALWAYS BEGIN ANY ELECTRICAL TROUBLESHOOTING WITH A FULLY CHARGED BATTERY.

Charge the battery overnight on an automatic charger with at least ten amps output. A trickle charger won't cut it.

Put a voltmeter on the battery posts and start the engine. On a 2003+ car, you should see around 14.5V for the first couple of minutes, settling down to around 13.5V.

While you're at it, check the tension of the serpentine belt. A slipping belt can reduce alternator performance. Another symptom is marginal AC performance, but you may not notice that during cooler weather.

Try those simple things and get back to us.

 

I think for now I am chalking this up to an anomaly. It only happened once and only while playing with my reader attached to car getting Jaguar related codes (not saying this was the cause but it was a pretty cool coincidence, all codes happened right as I clicked on connect). A single ride home in limp mode (or maybe limp mode + since my shifter had locked itself in park). I did already have the 8mm bolt walkout on the shifter cable and that was definitely different than this, in that case I could not really get it back into park. This, I suspect was from the overall communication error, probably did not know I pressed on the brake pedal, still can't explain why the tach, temp gauge and ability to get into park was fine for 10 seconds after it started then decided to fault out.

I did check all the voltages, they were good so I'll just wait for the next gremlin

Thanks so much for the responses on this, I'm learning a bunch about my new British friend (I can still call it British even though it has Lincoln and T-bird bits, right?)

Now back to my Lean burn issue but I think I have that whipped too

I'll leave this thread unresolved until I get through the cold season

thanks again,

Rick

 

What about the shrimps, and did you limp home in reverse?

Fingers crossed for a battery problem.

 

Rick, you may want to spring $10 for a little voltmeter thingie that plugs into your cigarette lighter. I have one (it also has a USB port for charging my phone) and it's nice to have peace of mind with the charging system.

I haven't had any problem with the charging system on my '02, but did on a Lincoln from the same era. Much of the internal logic seems to be very similar. What I learned (the hard way, of course) is that the little red battery light is not as simple as it looks. Years ago, on the cars with that idiot light, it was a very simple system. In nearly all cases, it could alert you to a problem, although often too late. The light compared alternator output to battery voltage, that's all. If the battery voltage was higher than the alternator output, that indicated a failure and the light would come on. For partial failures, with only a slight voltage difference, the light came on dimly and was easy to miss. That's how your father's Buick operated back when men were men, and women generally were not.

Throw all that knowledge out of the window. On our Jaguars, the light operates differently. In theory, the light stays off when the alternator's self-diagnostics say all is good. Light off = Alternator valid. Light on = not valid. Usually, I should add. If the alternator's control module suffers a total failure, it can't turn on the warning light. The battery will run down and you won't know until it's too late and other things start misbehaving. The alternator has to be at least partially alive or it can't warn you of a failure. It's a huge shortcoming. It's a like how a sick person can tell you they're not feeling well, but not so from a dead person.

Oh, so the engineers were aware of this and at least provided a backup warning, right? Oh, stop it, that's funny. When my Lincoln's alternator quit, there was no warning light or other symptoms for a while. The battery was still powering everything adequately for a short time. Then the AC shut itself off. I tried to roll down a window, and they wouldn't work. Next the radio quit, and eventually the dashboard went nuts and shut down most of the display. I was only a short distance from home, so limped the rest of the way with the engine barely running. As I turned into my driveway, I got a Low Voltage alert on the remnants of the dash display, WAY too late to be of any value.

Now I'm not sure what sort of offical low voltage warning our Jags might give, but you can likely expect all sorts of haywire behavior from other systems. That sounds like what you experienced. For $10 or so, you can keep an eye on the charging system.

 

How old are you? You know they make viagra for limp mode. I meen this is a car forum but whatever....

 

Realized I never put this as resolved. This issue never came back and limp mode no longer. Same battery and almost 2 years later and not all has been perfect but this issue never came back.

And sorry to whoever asked about my shrimp, yes, made it home fine and nope, not in reverse, once I go the shifter out of park, I could go to drive again.

It is a cool little ride but way too much over thinking involved for me, I like simple and this is not :-)