NEED help!!!
I just started having issue with my amber light w/cruise control not available coming on when i reach about 30mph then goes off at about 45.mph. This will repeat itself every time i stop and go never fails but if i accelerate fast the the light and message will come on earlier with a flutter of the engine that forces me to take my foot off the accelerator and accelerate very slowly.

Ive timed the visit to auto zone and when the light was on and tried to get the code read and the instrument said unable to detect the computer. So i went to a different auto place different kine of code machine and got the same reading. Is there a fuse or something that would prevent the code reader from making a connection with the computer?

Ive also check my PVC, cleaned MAFS, cleaned the sensor on top of the intake-i have new oil and spark plugs and filters done recent so i can cross of the list. ive trouble shot the brake booster hose with carb cleaner and only got a reaction from the front intake hose that goes into the fire wall. i sealed it up the best i could and took a test drive and still had the same symptoms. With out being able to check for codes Ive been trying the trouble shoot every possibility but im running out of option. Please help?

 

Dragonkat, open the hood and look at the wiring going to the driver's side of the throttle body. I have seen a few problems like this and what the cause was the wiring there is damaged and as you accelerate hard, the wires move and are shorting out, causing the computer to get confused. It may be possible that your throttle position sensor is dirty, leading to the computer loosing the position of the throttlebody, which will also cause it to fall into limp mode.

 

I just went out to check on that but not sure which one is the throttle position sensor and is it OK to disconnected and clean? The throttle body has a electrical connection on both sides.

 

Dragonkat, if you look, you have a small round one on one side and then a larger block on the other. THe large block is the one that I am referring to. This is the motor that opens/shuts the throttle. THis wire will sometimes get damaged and lead to the car getting confused as the command it is sending to this motor doesn't result in a matching indication on the throttle position sensor (the smaller sensor). This then has the car thinking there is an issue and therefore throws the CEL and various error codes.

Granted, if you are in there, might as well check out both cables as either one is a likely suspect, but normally it is the positioning motor cable that is the issue.

 

Thanks Thermo i believe you put me in the right direction i was concentrating mostly on a bad sensor. I check the wiring on both side of the throttle body and did not find anything out of place or damage.So i started checking along the whole wire harness and found a section that was a little to close to the belt and one wire was spliced. i repaired the wire and with the test drive i did notice a improvement in the performance but the light did come back on and if i punched the accelerator it will still flutter and the amber light will come on w/cruise control not available.

Also if it in the park position and i rev the engine there is a hesitation. It sound like a cough before it goes veerooom!

 

Dragon, my X is in the exact same condition as yours. Intermittent CEL and no cruise (somtimes flashing CEL) and my code reader says NO LINK with all code readers. It's the most frustrating thing I have ever dealt with honestly. Like you I threw many parts at it trying to fix it so far, upper/lower exhaust manifold gaskets, plugs, coils, water pump, thermostat, etc... and still same symptoms. Due to an inability to read codes, this is a real crapshoot. Thermo has been a great resource for me throughout this year long troubleshooting. You may want to check out the thread detailign my issues: https://www.jaguarforums.com/forum/x...nt-loss-53408/

I managed to get some codes pulled by the dealer when they rewired the OBDII connector (got me how this happened, but two codes, P1637 & P1638, lead me to believe the code reader problem is due to a bad instrument cluster from the ECM). After already shelling out over 2K in parts and labor, I have just decided to drive it until it dies (cat converter will go first I am guessing). I hope you have better luck than I did.

 

Thanks Queen it took for ever to read all of your post. you've been at this for a while anyone know the best place to buy gaskets sets since it looks like i'll be going in deep?

 

Dragon, the intake gaskets can be obtained from your local parts store. They will run you about $35 for the upper and lower gaskets. Keep in mind that the "intake gasket set" is the lower gasket set (between the intake and the heads) and the "plenum gasket set" is the upper intake gasket set. If you ask for the upper and lower intake gaskets, all you will end up with is the lower gaskets. You need to also has for the plenum gaskets. I know Advance has the gaskets.

 

yup, because it's trial and error without any hard codes. Hope you have patience, but maybe you will get lucky and it will just a vacuum leak. I purchased the Felpro head gasket set in case which included those gaskets in case i needed to replace the head gasket. They are available on eBay and some NAPA Auto Parts have them. My Advance Auto did not. Good luck.

 

Do you recommend i change the MAF sensor or throttle body sensor first before i start taking the engine apart? or would these not give me the symptom im have if there bad?