Hello friends, I have an issue.

I have a 2000 XJ8, bought it at 159k miles. Been a complete nightmare ever since. Got it cheap (atleast I think) $1600. Anyways, second week was a coolant leak/water pump replacement, next week was a rear main seal oil leak.

And just now, the main issue. Engine fail safe mode. I was driving back home on a short trip around the corner, out of nowhere my engine stalled and my car entered fail safe mode. I was baffled, got me by surprise. I went into limp mode to my house and parked the car.

First thing I did was read up on some forums and saw that it usually has to do with the cruise control related to a faulty brake switch. So that made me think, the night before I was driving home on cruise, and might have left it on when I parked and turned off the car. But I don't know if that messed up my car or not. Keep in mind, once my car went into fail safe mode, it would still start over every time and then after a minute would enter the safe mode.

Anyways, I had my mechanic come over and first thing he did was read up on the codes. Forgot what I got, but one of them was for the TPS, P1222 I believe. My mechanic took out the throttle body and cleaned it super well ($75). He then put it back in place, and we tried starting the car, wouldn't turn over.

I went to charge up my battery, thinking that it might have killed the battery starting it repeatedly. Put it back and reconnected, tried starting, and now its a whining sound, no crank, nada.

I then ordered the brake switch, had my mechanic install it ($40) and tried again, same thing.

I don't know what to do. No codes are showing up, and my mechanic thinks I need to replace the starter. Before I do that, any help?

 

Suggest you do an ECU / computer reset. I had similar problems and the reset worked for me. Disconnect the negative lead from the battery and touch the positive lead which is still attached to the battery for 10 seconds (to completely drain out the capacitors in the electrical system and wipe the memory). Reconnect the negative lead. Your problems should be gone.

 

Hi Michael,

Welcome to the Jaguar Forums! I'm sorry you're having trouble with your Jag.

A weak battery is the No. 1 most common cause of starting problems with Jaguars, and if your battery is old and tired, it may not be able to retain enough charge to provide the necessary current while cranking the engine, and if the battery voltage falls much below 11V while cranking, the Engine Control Module (ECM) will not trigger the ignition to fire. Have you tried jump-starting the car with another vehicle? I've found that when one of our Jags has a flat battery, it needs to be hooked up to another vehicle for a good 5-10 minutes to get a basic charge going in the depleted battery before the Jag will start.

The Diagnostic Trouble Code (DTC) for your TPS was probably directly related to the car going into Fail Safe Mode/Limp Home Mode, but low battery voltage can cause random DTCs to be triggered. I am attaching the 2000 DTC Summaries manual so you can look up your actual code and possible resolutions (The P1222 you mentioned indicates a problem with the Pedal Postion Sensor).

Has your mechanic checked for battery voltage at the starter? Has he checked the starter relay? Lots of other possibilities and it is highly unlikely a bad starter caused your car to go into Fail Safe Mode, so I wouldn't pay for a starter just yet.

You can download the 2000 X308 Electrical Guide here:

http://www.jagrepair.com/images/Auto.../jagxj2000.pdf


It's almost 1:00 am and I've got to get to bed, but I'm sure some of our knowledgeable X308 experts will have some helpful ideas.

Cheers,

Don

 

I went to get my battery charged, and the guys told me I needed to replace it soon. It got 650 CCA, and 12.2 V. I had another battery from my SL500 that was fine, and I used that to try to get the car started since the other battery needed to be replaced. Even by doing that, it still wouldn't crank. Also, some more information, when my mechanic took out the throttle body, he did not disconnect the battery. I believe because he did this, it messed up the ECM and caused the car not to start. I assume this only because my car was starting fine before even when the problem first persisted.

 

Left side under hood is a relay box - open and wiggle all relays around, enough to make their pins slide in the mating socket's contacts - see if starter will now turn over. Every time my 308 fails to crank (usually after it's sat for a while), this does the trick.

I always say (after this has worked) that NEXT time, I'll do it one relay at a time, so I can figure out which one it is... but then when next time happens I'm in too much of a hurry, lol!

 

The relay on the right end of that group of relays, or the bottom of the "T" of relays, is the Ignition Positive relay, a very likely culprit. The relay next to it is the Horn relay, so you might try swapping those relays to see if things change.

Cheers,

Don

 

It is possible that your TPS now needs to be recalibrated, which is technically a dealer-only process, but there may be a DIY method. Search the forum for information.

Cheers,

Don

 

After a hard reset it recalibrates the throttle, on ignition the idle climbs to 1800rpm then decays back to almost stall point, let the car sit and idle for 10 minutes so it gets the chance to store the new maps.

Most people don't do this....in fact most people don't disconnect the battery before working on them, all I can say to this is 13 computing modules dont like it.....

Back to the original post, is there a click from under the bonnet when you go to start the car?
12.5V minimum on the battery, buy a new one.
159k = throttle rebuild time...P1222 will not be fixed with a super clean of the TB, it's a worn out sensor and the fault will only get worse, shorter periods between failsafe modes.

 

+1

if all else fails follow the drive cycle info in JTIS / codes PDF.

 

[QUOTE=Don B;1285722]The relay on the right end of that group of relays, or the bottom of the "T" of relays, is the Ignition Positive relay, a very likely culprit. The relay next to it is the Horn relay, so you might try swapping those relays to see if things change.

Cheers,

Don[/QUOTE