This post started 3/20/2009 by Bull 27 who discontinued posting on 4/22/2010 covering the Limp Home Mode and has ended up taking a twist and began covering Fuel Latch Door as my esteemed colleague had mentioned. When posting you must keep in mind you would be best served by starting a new post. Not all situations are the same and in a long thread the message along with the results could be lost. Use it as a reference if you must but do yourself a favor and do not hijack a previous post and stay on track with the post.

 

2005 STR, Park Brake Fault, Total Shut-down.
Docuzzie: I had the same problems in early Jan. during heavy rains, local foreign car mechanic (not Jag specialist) found blown fuses in passenger-side fuse module, changed fuses, I drove it away. Next day after driving a lot, took it to a car wash, drove 1/4 block, Park Brake Fault returned and I was again 'dead-in-the-water.' I purchased it w. 40k miles on it, drove it to 50k, took it to dealer for last warranty ck/oil change and it ran fine until it RAINED. My local dear mechanic found that a shroud over the wiring harness from the windshield where water runs into the engine compartment had been removed & rain or carwash water was shorting out the system at the right-rear of the engine compartment & blowing the same fuses over & over. If your shroud is still there, it could be leaking water.

 

Ok, I had the work performed on my 2005 STR Yesterday. The codes generated and stored in my module were the following:

>The fault codes that are stored in the module are;
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>P2135 - Throttle position sensor A voltage correlation error
>P0128 - Thermostat range/performance error
>P0174 - System too lean
>P0171 - System too lean

(I thanked the Service manager for providing me this information) The applicable services performed were the following with their associated costs...

Body-Throttle Unit Price 720.58 and an associable gasket. The Parts and labor for this was 893.08
Thermostat 61.25 antifreeze 45.00 Parts and labor 336.25

There is no mention of re-flashing the ECU which could mean mine has already been done or perhaps they'll get to it later. They may even have neglected to place it on here as it's a warranty operation. I will contact the Service manager and ask if that is an operation that was performed. Additionally, they suggested that I change a leaking coolant hose at the cost of 510.00, along with brake booster o-rings @ 370.00. My extended service warranty company refused these two things, but told me, if the errors return, they will take care of the hose, and instead of the brake booster O-Ring which they felt sounds like a "Re-build", they would replace the brake entirely. I have a trip to New York City scheduled for this weekend so we will see.

 

So, to make this relevant to other users. The most likely cause of the "Limp Mode" issue for the above would be water getting on the connector to the Throttle Position Sensors. On all 4.2 cars the Throttle Body is on the rear of the engine by the cowl (on the 3.0 it is on the front by the radiator). More than likely the service organization that did this repair, replaced a throttle body for no reason. It is likely that the issue may reappear since the cause of the short at the Throttle Position Sensor was not addressed.

 

JOsworth, thanks for the input. I hope it rains profusely on my trip or soon there after which provide me an opportunity to share more of the experience with this forum.

 

+1

 

You won't. It's a Jaguar most parts are dealer only.
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I had the same problem and solved it by cleaning the mass airflow sensor and throttle body - that solved the problem for a while (See previous posts). On 11/8/11 the problem reappeared and I finally took the car to an exotic car expert (over 30 years working on jags, ferarri, lambo, astins, etc) and he informed me that the "engine fault, dsc not available and parking brake fault" issue is common and has nothing to do with the mass airflow or throttle body. I was explained the following: there is a separate diagnostic computer system that monitors emissions (the system is contained in the same wiring harness as the other wirings). This system sends out a signal to the engine then to the transmission then to the wheels. The purpose is to make sure that those items are performing with specified parameters as set by emission standards. Typically what happens is if the signal does not make the proper loop, the system starts shutting down various items (i.e thus check engine light, DSC not available, parking brake fault, etc) and places the car in limp mode. The solution is to pull the codes and to test each module in the system to find which module is causing the problem (i.e. not sending the signal so as to complete the loop). The system has been installed on a lot of cars (not just jags) for the past 10 years. Unfortunately the problem has been occuring mostly in jaguars. I hope this helps. I will provide an update once I get my 2004 S-Type back (I just took it to the shop yesterday 11/9/11 for the "engine fault, DSC Not Available and Parking Brake Fault)

 

esipp,

If you still have the factory battery, you may simply need a new one. Your particular issues are very common when the battery is dying. Lights flash on the dashboard and faulty codes get thrown. Search "battery problems" and you'll come up with quite a bit of reading to do....

 

Well in a word---NO. I would find a different mechanic. There is no special emissions computer.

The rest of his explanation is non-sense. Jaguars have nothing special compared to other cars. There are no signals sent to the wheels. These errors from the DSC and the EPB are from different reasons. Sometimes a component failure, sometimes a connection problem. The best people to solve these problems are guys that actually work on Jaguars. That’s why Brutal has been such a great resource!! He sees these cars all day long.

There are just less of them on the road so the knowledge and parts are not wide spread.
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Most of that is gibberish. Please don't post it again as it just adds confusion.

The actual way these cars work is in jag's documents (JTIS, Tech Guides etc). Just read those if you want to know how things work.

 

Thanks for the info. If I knew the difference between gibberish and real deal I wouldn't be looking for help from the experts on this forum.

 

Hi,

As posted earlier in this forum, I have found that these faults are caused primarily by a load of bad gas and can be eliminated by regularly adding a moisture inhibitor (dry gas) to your tank. I do it about every 5 tankfuls. I have had no faults since doing this. It is a lot cheaper than replacing any parts or even visiting the Jag dealer.

Try it! You may find it works for you.

Jeffg
2005, S-Type, 4.2 V8

 

You could read the actual jag documents.
You could read existing posts on here (and other jag forums).
Don't trust the guy who told you the gibberish.

 

Believe me when I tell you...on one rainy night I experienced 7 limp mode occurrences and only had a mile or two before I got home...I got FED-UP and went thru this forum and posts until I came across the instructions on how to fix this problem, an I did, thanks to the wonderful info that JAGUAR drivers had documented in the FAQ...trust only the people that drive these cars daily!!

 

I had this problem the second day i bought my car five years ago . I took it to a local tech. he said the problem was the piece of the throttle positoning sensor that was on the gas petal . It has been a while but i think he charged like six hundred the next time it rained real hard same problem i went on some jaguar forum and read there was a recall on water running down onto the electrcal part on the gas pedal . I went out with a hair dryer stuck it down by the pedal for five minutes or so started the car and it was fine on that same forum they suggested putting a plastic bag on that piece havent had a problem since four years ago . I dont know if i just got lucky or if it the problem is the part on the gas pedal.

 

Had the same problem a while back and took it to my local Jag dealer expecting the worst. Usually it's the cats that go bad, but it was just a pipe that leads to the cats and they replaced and all is good. I love my 04 S type.

 

I have 03 s-type, and I having same problem... However, the mechanic says its the pedal position sensor, but parts store say I have to purchase throttle body to get sensor..costly...Did that solve your problem?

 

There are 4 sensors: 2 on the TB and 2 on the pedal. If you try to replace any be very sure to get exactly the right one. I think all 4 are different.