i took my 2001 xjr out for a local drive after 2 weeks. drove it almost all day without a problem 5 to 6 trips around town and highway run. on my way back home i decided to get it a car wash before i garage her again.

while waiting at a red light. i got hit with "traction/ASC not available" "engine fail safe mode" light turned green and i had no throttle control. car moved about 10mph. pulled to a side road. turned the car off. and started it again; thinking it would clear the codes. it did not. still same codes.

Drove her about 4 miles with 8-10 mph on the side of the road back home. engine idled fine no jerks or weird noises.

got home;put it in park gear and idle jumped to 1500 rpm turned the car off. went to get my OBD2 reader from a different car. grabbed it and returned to the jag. started her up...and....no codes...runs like nothing happened. ....

i have had her for about a year and she has never done this before....
ive had the Traction light and asc light before but once moving they clear themselves. ... the engine fail safe is new...


anyone have an idea why she did this??? does she just not like car washes??? ill wash her at home i swear if she does not mess with me like this!...

 

I've had the same thing happen to me all the time, my ABS light comes on and ASC/trac not available displayed, only once has it gone into failsafe mode. Usually restarting the car makes it go away.
List of solutions I've seen on the treads, though I have yet to try these myself are:
checking the battery to make sure it good, supplying the correct voltage, and that the terminal connections are tight
cleaning the abs sensors
opening the traction control module to repair broken soldering

I've yet to do any of these myself, because like I said,my warning light has always gone away just by restarting.

One quick question to had on; what is the difference between the ASC and the Traction control? They seem like they both do the same thing,so whats the diffference and how do they work with each other?

 

Did you have the problem on the way to the car wash, or after?

 

any idea on whats causing the engine fail safe mode? i did not get a chance to read the codes because they disappeared when i started the car up again....ill keep an eye out...on my next day off; if she does this again ill read the codes without restarting her...hopefully it was just a hiccup.

but i will try those suggestions! on my day off just to double check. i should probably get a battery tender.

to answer your ASC and Traction control question...ASC stands for Advanced Stability Control ...its primary job is to make the car go in the direction you want it to go....for an example you are on a icy road and approaching a turn ..ASC will monitor tire rotation on each tire... and reduce power to that tire in order to maintain that turn and correct outside tire rotation to complete that turn.

Traction control is the rubber meets the road...basically in charge of keeping grip on the road....say if you were doing a burnout in a straight line....Traction control will turn on but ASC will stay quiet unless needed.

now say if you were doing a burnout and turning at the same time....they will work together in getting the car in the correct direction and trying to gain its grip....they work together in that situation...

this is the part im not 100% about...how they work...they reduce the power to the wheel somehow...maybe is magic??? who knows loll but most likely brakes or differential??


RJ237: i was in route to the car wash but then that happend. loll

 

Given the age -- I would bet it's the throttle body.

Yes -- a weak battery will cause problems ... as will a faulty solder connection on the ABS pump. They don't seem to cause the engine issue ... and if it goes away .. and the battery is not old ... I think the T-body. The ABS problem -- will only reference the ASC/ Trac and the light for the ABS.

..... have never had a brake switch issue.

I have had both issues recently. "restricted performance" .. and "failsafe". A number of years ago -- I had the "failsafe" about 5 times in one month. Back then the codes referenced the TPS on the T-body. Since the car was not used often and the TPS suffers from dirt build up on the contacts -- I tried pushing the throttle to the floor (engine off) to clean the contacts. I did this about 50 times initially ... then about 20 times before I started the car everyday for a week. It went away for a couple of years.

My recent issue last month -- codes are referencing the PPS on the T-Body. It's a similar sensor design. The two sensors are on each end of the t-body.

I went through the codes -- had trouble initially clearing them ... but eventually did and .. the car ran normally. It's a really annoying problem. I'm going to get mine rebuilt (T-body) ... It a shame Jaguar does not sell the sensors.

The computers are always monitoring the PPS or the TPS -- they are duel track sensors. If any fault is found with either sensor the car overreacts ... since the car is computer controlled the ABS, traction, cruse control or even the engine management can't be sure where the throttle or the pedal are at that moment.

Jaguar sells the T-body -- it almost 3k.

 

The throttle body can be rebuilt if it's faulty, ASI is one source. Link below.

Automotive Scientific Inc. | Quality Rebuilt Automotive Electronics | Rogersville, TN

 

I have been driving with no ASC and trac off on my XJR for over 3 years now with no problems, mine is caused by a bad solder spot on the abs pump. I couldn't get the bottom screw out without moving break lines so I just left it. This maybe your problem but it may be a bad throttle sensor.

 

+1 @ throttle body & battery.

 

thank you for all the input guys n gals!

i was able to rescan the car yesterday before going to work...this is what it showed in pending codes (on that day i did not clear codes because when i restarted her she did not throw a CEL but yesterday i did a rescan and found pending codes...still no check engine light tho) P1000 which i believe is a self test code....the other was a P1121....any advise/suggestion on that??

 

https://www.jaguarforums.com/forum/x...lebody-114757/

 

You mentioned build up on the TPS, is it possible to clean it with something like MAF cleaner or electronic cleaner? What about the PPS?
I've had the ASC/Trac warning come up, and only one the failsafe, but I've never seen a CEL, I wondering if my issue is with the abs sensors or soldering.

 

Thank you Bcrary3! cleaned and all is good!

so far so good thank you everyone who helped out....what i did was clean the throttle body with a lint free cloth with CRC Throttle body & Air-Intake Cleaner...sprayed it on a rag and used the wet rag to whip it clean as possible....a lot of junk came off! then used CRC QD electronic cleaner for all the connections and used a light coat of Dielectric connector protector. ...theres a pdf floating around if someone is interested in the instructions. i also have the PDF saved if anyone needs it.

after all that took her for a 30+ mile drive. drove her carefully the first 12ish miles then mashed potatoes for her loll she responded well b

OUScooby: yeah the soldering is probably what is causing your abs/traction lights....i get them as well its itermitted and probably on a weekly bases but never permanent ...always appears upon first startup after a while and then first stop sign the CEL lights clear.

 

intermittent issues, especially those that can be caused by multiple factors are very difficult to find. The very early cars did have an issue with dissimilar metal corrosion on a connector -- but this was fixed in later vehicles.

When a problem only pops up every few months -- it's next to impossible to find the problem .. unless one code directs you to a failed part.

 

Glad we found a solution to the problem! I clean my TB about once every 6-9mos. I am planning to send it off to MaxBore this winter to be bored out to get more power, that combined with my 3" custom aluminium air intake, she will hiss more than she purrs. >

 

alright guys update...after driving her around for 140ish miles all was good until i parked her and started her up a few days later...this time soon as start up it had P1122 this time not P1121...let her warm up and turned her off and started her again...and again all is good no CEL light. i now bought a battery tender from harbor fright...a 12v 750ml maintainer with float charger about 20 bucks...it was red (charging for about 2 days) and now it is green...i wonder if it has to do with a low battery...because each time previous with P1121 i got ABS/TC light with a CEL. same story with the P1122 this time. is this normal? does the throttle wire harness tag along with the ABS/TC module wiring? wondering if there is a short somewhere....

but if it becomes frequent i guess a new throttle body rebuild? anyone had theirs rebuilt before? also i noticed i have a ton of slack in my throttle cable...maybe i should tighten that down some and see if it reoccurs?