Seeking assistance to resolve this issue.

I have done a search on this forum for the stated issues, and I was somewhat discouraged by the results I read about. This seems to be a hard problem to solve, very expensive, and maybe not solvable at all.

Wifes car is going into LIMP mode.

In the past (several years or so) the car has done the stuttering on acceleration problem but it turned out to be the air filter clogged up and the large tube for the CCV on top of the engine. Car ran as it should after those fixes.

Now suddenly and abruptly the car is randomly going into LIMP mode. I have read about the TCM, Throtle Body, etc.. Not sure where to start.

The other thing is the thousands of dollars I have read about paid to the dealership with no resolution and the Jag dealership still not knowing what the problem is.

Where do I start????

 

If the car is going into limp mode, then it should be throwing codes. If you have a code reader then start there. If you dont, and can swing it, you should pick one up. They are pretty inexpensive these days. Of course you could just go to Auto Zone and get it read too.

Once you know what faults are sending the car into limp mode (as there are several things that can) you can get on the right track to diagnosing the problem.

 

update... wife just went to the store and the car crapped out into LIMP mode 3 times. She said every time it happened she was stepping on the brake.

Any thoughts????

 

Codes are:

P0171
P0174
P1000


Auto Zone would not clear the codes for me. Nor would they allow me to use the code reader. They must be having problems with people not bringing the code reader back. IDK.

I took a look at the car today.. couldnt find anything wrong. But I did check all the electrical quick connect plugs on the intake manifold and the MAF Sensor. All looked good with not corrosion. Checked the air filter and it looked ok. checked the electrical quick connect plugs on the firewall by the vacuum line next to the brake booster.

IDK guys... the car drove fine for me after I did all that stuff. I drove it hard, braked hard, etc.. no problems. That was about a 10 mile round trip.

Any ideas?????

Thanks

 

Mine had the engine malfuntion light on last week, Feb. 13th, along with the cruise not available message. I got real lucky but as soon as the light went on I stopped and filled my tank even though it was over half full. I thought maybe I had some bad gas or something (have always used premium). Light was still on but I could turn on the cruise and it worked. The cruise warning would stay off for a little while but come back on. It was a Sunday so went to Jiffy Lube and they hooked up the computer to see why the engine malfunction light was on. It told them it was a transmission something or other and a dealer only fix. Got the oil change with air filter I bought at Auto Zone since they didn't have one. The lights and warnings were off for about 15 minutes and came back on. Used the cruise again and the message went off again but this time stayed off. Went to work the next morning with the engine malfunction light on. Never went into limp mode but was expecting it. Called my mechanic while walking to my car after work to make an appointment for him to look at it. I start the car while talking to him and no light. I told him that I expect it to come on in a little while and he said that it won't and it hasn't, knock on wood, for over a week now.

Here's his explanation of what he thinks happened and I never told him what I did once the light came on. He said that in '96 the government made a law that the light will not go off on its own without going through three complete cycles of driving without the problem that caused it in the first place, (not just a ride around the block, but good drives). He said my problem was probably just a loose gas cap which is when I thought about filling it up I probably tightened it like I normally do (at least three clicks). So, my suggestion to you is to first buy a new gas cap, could be the least expensive try for a fix. Probably not, but you can hope. I got lucky without even having to replace the one I have.

 

P0171 is a lean code on Bank 1
P0174 is a lean code on Bank 2

P1000 is an indication that the self diagnosis was not compleated for some reason.

I wouldn't worry about the P1000 for now as it should reset itself once the repairs are complete.

The lean codes however, basically the whole fuel/air system was at some point, if not always, running lean. This may exist if the engine is sucking in too much air and/or the fuel system is not delivering enough fuel.

I found these possible solutions for you:



Air can enter the engine through a vacuum leak (Jag 2.5's and 3.0's are notorious for this, especially the IMT o-rings), dirty airflow sensor, an EGR valve is not closing and is leaking exhaust into the intake manifold, an EGR valve that is allowing too much flow (because the EGR differential pressure sensor that monitors EGR flow is faulty and is under-reporting EGR flow).

If the problem is not enough fuel, it may be a weak fuel pump, restricted fuel filter, leaky fuel pressure regulator or dirty fuel injectors.

 

I think I am going to start with the least expensive things first.

1. IMT O-Rings
2. Fuel filter
3.

 

First you need to determine if it's a vaccuum leak, get a 2' length of 1" heater hose, put one end at your ear and pass the other end over the top of the engine, paying closer attention to the vacuum hoses and the IMT area. Works like a stethiscope, I use use one to balance carbs on my bike and to find hard to find vacuum leaks. If its a bad leak you will hear it as soon as you open the hood. O-rings are cheap and a 10 minute fix. You should change the fuel filter regardless and it's probably 50.00 and a pretty easy job.

If it'sneither of these then you might have to look at something more expensive like your MAS.

 

I agree with Sidewalkman. Try to find a vacuum leak first. If you havent yet dont the IMT rings, its not a bad idea to as the stock ones flatten out and leak eventually anyway plus its cheap and easy to do. Chances are, that won't be the fix for your car though as there are many points that can fail.

You may end up money ahead to pay someone with a better OBDII scanner to run the real time data on your car. You can see much more than just problem codes on better systems. You may just find the exact problem there.

 

My '05 had the same two 0174 and 0171 codes recently. As stated before you should check for vacuum leak first, but my problem was the MAS and I got a new fuel filter. Not a terribly expensive fix, if I remember correctly the garage near my house asked about $350 for both.

This is a question for everyone, but if it was the o-rings shouldn't he clearly hear the leak just by opening up the hood and listening? When my codes were present I tried listening all over the fricking engine, but couldn't hear any clear sign of a leak. Just trying to save you some time/effort.

 

in my case somedays you would hear the leak and somedays you wouldnt. Its funny because as soon as i got rid of the 171 and 174 with the o ring fix the very next i had limp mode at least 15 times and it got worse and worse as the day went on. Then the pulled the battery for a couple of hrs and that helped alot. then i let it sit for a week( with the battery reconnected) and lo and behold it never happened again. a week after that i changed the Fuel filter just for good measure ($10 5mins) and so far (crosses fingers) its been fine.

 

So I replaced the IMT O-Rings. The old yellow ones were shot. They were mashed flat and there was dirt getting in and im sure they were leaking.

I also cleaned the Mass Air Flow Sensor. (I am assuming this is the item between the air filter and the throttle body) This was very dirty and I cleaned it with the CRC mass air flow sensor cleaner.

I also cleaned the throtle body opening where the butterfly valve is. This was also very dirty. Used a standard throttle body cleaner for this.

So, now the car is not going into limp mode and it seems as if the problem is gone.

However, there seems to be a new problem. As you are driving normally, if you take your foot off the gas pedal the car sort of like downshifts or jerks to a slower speed. Also, when the car is put into Drive, the RPM's come up to about 1100 and the car seems to want to go on its own with no assistance from the driver. (thats wierd!).

Thanks again..
Andy

 

I belive I read somewhere here that it is not a good idea to spray cleaners into the
throttle body. Something about a special coating. Perhaps someone else will chime in on this???

 

Well I read several threads on here about using throtle body cleaner and i didnt read any negative info.

 

I have just had my car tested for same fault. The computer stated "Driving Speed Signal" was the problem and quoted Fault code P0575.
Does anyone know where the sensor is located?
Where can I get a replacement?

 

When I try to lock car using ket fob, the horn toots twice. All doors and windows closed as is the boot. Aftre a while the alarm goes off.
As above I also have problems with "Cruise not available" Code P0575 states Driving Speed Signal.
Could the two faults be linked?
How do I resolve the problem?

 

Carson, what happens when you lock it with the key and hold it in the lock position?

 

Sidewalkman, when locked with key, alarm sounds twice but does not come on later. I have not tried holding the key in ocked position but will try tonight after work.
What does hoding the key in locked position do?
Kit.

 

when you keep it to the right (i think) it locks the doors, closes all the windows and sunroof. You obviously have an open curcuit someplace, likiely the trunk or hood, maybe a wire off. When you start driving do you hear all the doors lock after you hit 5MPH?

 

Sidewalkman,
appears to have done the trick, tried it on Saturday morning. no problems with alarm so far.
Thanks
Kit