1998 XK8 check engine light on with code P0714 and P0706. Neutral safety switch replaced by Jag mechanic, but check engine light came back on after driving only a few hours. What else could be the cause? Diagnostic on torque converter seems to be ok. Also transmission is NOT exhibiting any symptoms of transmission problems, I.e., it is not lurching or making any odd noises; the engine appears to be working fine. The torque converter was replaced in 2009 so I find it odd that it would be faulty again so soon. Does this require major transmission work? Or can the sensor be checked without replacing the transmission?
Engine: AJ26 V8 4.0
Lja 6201 AD Neutral safety switch replaced by mechanic but check engine light came back on after one day.
Hello and welcome to justanswer.comCan I have the last six digits of your VIN?
Hi, the last six digits of my VIN are 021414
Ok thanks. XXXXX could also be for the D4 switch which is a micro switch on the J gate that tells the module that you are moved into manual mode. Even if you only use standard drive this switch can still be the cause or it can even be the cable that needs adjustment or is stretched. For the other code I assume it was a P0741 not a P0714. I can tell you that this is either the converter or a stuck valve/regulator in the valve body. We should first check the fluid level and condition. Since there is no dipstick a fluid level/fill plug needs to be removed from the back of the transmission while the engine is running and the transmission fluid is warmed up but not hot. The vehicle needs to be on flat ground or a lift making checking the fluid difficult.
Hi Richard, so are you saying that I need to confirm with my mechanic that the code was P0714? Are you saying that because I'm not experiencing the transmission problems associated with P0714 that the actual issue is related to 741? Does that seem consistent, in your opinion with why the check engine light would go off and on intermittently?
Yes on your vehicle there is no P0714 which is why I think they meant P0741. Also ask if there are any codes in the ECM.
Ok, thanks Richard. Is checking the transmission fluid as you described earlier a time consuming task? How long would this normally take to do and shouldn't my mechanic have done this in the first place? As mentioned, the work was just completed 2 days ago and the shop I use does have a service warranty so I hope this is covered. Was the neutral safety switch I mentioned in my original question even related to this issue?
Also forgot to ask, does this type of work typically warrant changing the entire transmission? As mentioned, the transmission and torque converter were entirely replaced and rebuilt in 2009 at 66K miles. The car has 95K miles now and eventhough this is about 30K more, how likely is it that the entire transmission AND torque converter would have to be replaced so soon? It seems to me that replacing the transmission every 30K miles is a bit extreme, don't you think? What are your thoughts on this?
I am worried there is a mechanical failure and the fluid can be contaminated by metal or clutch material. The first step would be to check the fluid level and condition so you would think the mechanic has done this already. The neutral switch is fully electronic and could have been the cause of that P0706 code. If it is just a stuck valve/regulator this can be done with minimum tear down but if it is a converter issue then the unit does have to be removed.
Considering your last reply, yes the neutral switch was fixed to address the P0706 code. With the exception of that check engine light, the car appears to be running fine, however I am wondering if there are other warning signs I should be looking at or listening for to indicate that the transmission fluid might be contaminated? The jag shop I use is really busy, so I usually can't get a hold of my mechanic until later in the day. As mentioned, the car does not lurch or have issues shifting gears. It's an automatic, under my shop's service warranty, and generally does not "feel" like it has any other mechanical failure issues. What kinds of "mechanical failures" would typically cause metal or clutch material to seep into the fluid?
In most cases the forward drum cracks which causes the contamination but since you do not feel any problems shifting I suspect it is either the converter or regulator/valve body for the torque converter. You generally will not feel this but the TCM will detect the fault and turn on the warning.
Thanks Richard. A few more things, although this does not seem to be the issue with my car specifically, what would cause the forward drum to crack on XK8's from this production run? and how do I protect this from happening to the transmission of my vehicle :) Is this a known issue that happens to these cars after reaching a certain number of miles? Also, curious to know what the general price range is supposed to be for the neutral switch replacement mentioned earlier? Also, what factors contribute to the malfunctioning of the torque converter in the first place? I ask this because it seems that if the issue is the torque converter, this would be the 2nd time within a 3 year time frame this would have to be done - which does not seem to be very efficient. Are there certain transmission specific care and handling tips I should be aware of as I push the 100K+ mark on this car? It also appears that quality torque converters would have a 5-year warranty. Does this hold true for Jaguar parts?
The drum is just a high mileage failure in these units that we see. There have been more robust parts that are installed to correct this. Since you have the transmission overhauled the latest parts should have been installed. I will look up the current price for that sensor. As far as the converter the one that was installed was most likely a re manufactured one so it is possibly the internals have failed.
Thank you Richard for your thoroughness, I appreciate it. I will be sure to give you the best feedback when my seemingly incessant questions come to a close for this thread :) So, to add to your last reply, could you also let me know what to expect price wise for a standard torque converter replacement vs. a high-end, beefed up one with a good multi year warranty? I want to see if it is truly in-line with what I am hearing. Thanks.
For a quality converter you would be looking at about $800. A new part from Jag is $1750. The neutral switch is $550 new from Jag.
Thanks. Also, if it's not the torque converter and it's just the regulator/valve body for the torque converter, are there parts for that or is that mostly labor?
If it is the valve body this is also costly as new part from Jag is over $3000 but a trans shop should be able to source one from the manufacturer for about $1500.
12 years at a Jaguar dealer as technician and shop foreman.