If you figure out you need a throttle body have your own rebuilt for less than $300. It comes with a lifetime warranty and is by far the cheapest option.

 

Ok all, 1 week ago I received the DSC error with Engine Systems Fault. After reading here I added dry gas and filled up (from half tank) at a name brand using 92 octane. Car was still in "Limp Mode". The next day I started the car and noticed I had control of my gas pedal...for about 2 minutes. The next day I had control of it for 5 minutes. The third day 5 minutes and of course it went away again. I left the car running for 4 hours and when I returned it was still in "Limp Mode". I turned it off and back on and it ran fine...so fine I drove it all day (about 100 miles) with many stops having to turn it off and back on and it was fine all day. The next morning it went straight into "Limp Mode" and I cant do anything. I have replaced the Mass Airflow Sensor with no avail. Any ideas??? I wasnt sure since mine kept coming and going if it could be the TCB.

 

Stanbraxton asked "any ideas" re. the limp-mode problem. After I wired a 68,0000microfarad capacitor + 20microfarad foil capacitor + a series fuse of 5amp. across my battery, I have NOT ONCE had the "restricted performance" signal in the lcd window. Previously I would get it every fortnight/2 weeks or so -- and it was as it said, def. restricted. This capacitor combo has been in use now some 6 months or so.
Leedsman.
p.s. I used crocodile/alligator clips to affix to battery terminals. Cost? Afew quid.

 

Ignoring the last post for now because it is likely irrelevant, stanb you need any stored codes, preferably from both PCM & DSC/ABS - unless you may have a failing battery. Do you know how old it is?

Please put your car details in your signature as otherwise it just leads to a mess. You can't have Leedsman's type as the diesel S-Type wasn't sold in your country. (It also uses a PCM not used in the rest of the range, I understand.)

Any OBD tool should read the PCM but very few will read the DSC/ABS. Maybe start with the PCM (AutoZone/PEP boys can read it free) but don't forget you'll be trying to diagnose a fault which apparently originates in the module you've not read. Without any codes you could be changing parts at huge expense till you get lucky.

 

Leed's... Limp mode and Restricted Performance are two totally different things....

Stanbraxton... Need much more information... The intermittent nature of your problem, unfortunately, makes it real hard to figure out. Codes are real important at this point, plus the car details... Basically what JagV8 said...

 

Well, this thread goes on and on -- 121 contributions since the original from Bull 27. My suggestion, intending to be helpful, costs just a few dollars, not hundreds, and is FACTUAL on my car, not guesswork. There is of course no guarantee that it would work on another car; but for what it costs, it's worth a try don't you think? Especially when you have exhausted all other possibilities, and taxed all the brains on this website to the n'th degree.
Interested parties might read a contribution of mine in the "tech. help" section where a different kind of thinking is required for bottoming these problems.
Nontheless, that doesn't mean the older problems aren't there too. My S-type has just failed it's MOT (UK gov. safety check) on rear wishbone bushings being worn -- nothing exotic about that!
Leedsman.

 

Yeah, but the last poster (stanb) only just posted so as yours is the only car ever heard of with the particular problems you described & apparently fixed it would make sense to check for the more common faults first.

 

Hello and I am sorry for not posting the needed info:

The error codes are:
P0430 - Catalyst Efficiency Below Threshold Bank 2
P0447 - Evap Control System Vent Ckt Open
P0450 - Evap Control System Pressure Sensor Fault
P1215 - No information about this error code
P1344 - No information about this error code

My vehicle is a 2003 S-Tpye V8 4.2 Base. Any help would be appreciated

 

i have a 03 s type 4.2 with 136k on it. Mine just started this exact thing. i am going to try cleaning connection first to see if that works. I was told on 03 model tps and throttle body are sold as one piece for 800 and some change. Is this dealer only or can I find cheaper.

 

Do a search, or just look at the replies in this very thread.

 

Have a look in the forum stickies and grab the code PDF which lists the codes and lots more detail per code. I'll just put brief info but the PDF gives far more that you need.

P1215 APP sensor sense circuit low
P1344 APP sensor sense circuits

If there's any chance you have an old or failing battery, change it because otherwise you could spend a fortune changing the wrong parts.

I'd clear those codes and see which reappears and when. You want an OBD tool so that you can read the system every day until the OBD monitors set. (If they don't then you will be fault finding based only on what you know so far.)

I'd get either an elm327 (ebay $20) or a handheld unit (but make sure it does report OBD monitor readiness status), probably $50-60.

So far, the EVAP ones would perhaps also account for the cat fault so just one issue might account for 3 codes.

 

Can you tell us exactly where the Throttle Body is located?

 

You desperately need to get hold of JTIS (see FAQs etc or ebay). I wouldn't mess with the TB without reading plenty about it first, then you may well decide to leave it alone. Check its price, too, as you could wreck it and need to replace it.

 

..I thought to do a hard reset, is to take the negative terminal over to the postitive and hold it there for 15seconds or more, can someone chime in on this, Thanks

 

It can't matter which way you do it but don't touch the two together straight away. You're trying to drain all charge but not suddenly. 5 mins disconnected would be plenty. No need to touch them together at all. Remember this will ONLY reset a few of the modules, mainly the PCM. Not the TCM.

Clearing the PCM this way LOSES all stored codes and associated data for ever. It also clears all OBD monitors (which you need to be set to pass I/M etc) and the learned values for engine behaviour including misfire detection. And more. In many cases this doesn't matter but in some cases you end up with monitors that will never set and codes that will not flag because the monitors won't set. Good luck with diagnosing the issues......... (Obviously, passing I/M would be "tricky".)

 

Ok...I tried just about everything. The only way I can get my car to run ok is to unplug the battery for about 15 minutes then I get a few days out of it. Does this appear to be a problem with the PCB or TB? Also, does this have to go to a Jag dealership or can a ford dealership diagnose also?

 

I just unplugged the battery again for 15 minutes and its working just fine. I changed the battery a few months ago.

 

Clearly you have one or more faults. What you are doing is not making the car run "fine".

You may or may not have codes, and in any or even many of the modules. If you save a few $$$ by going to Ford but get only some faults found, quite possibly with the wrong meanings, that would not by a saving but a nightmare.

I still cannot see your car details in your signature and am unable to comment further because you still have not added them.

 

Ok...I took the car to the Jaguar dealership and paid the $110. They said it is possible the Accelerator Pedal Position Sensor. Is this the same as the throttle position sensor??? How do I identify it so I can replace it.

Thanks,

Stan
2003 S-Type 4.2 Base

 

No. There are 2 APP sensors where you'd expect and 2 throttle ones where you'd expect. Worth using Search to see what happened to other people and what they did.