hi all new to the jag scene anybody have any recommendations I have a 1996 jaguar xjr6 I bought recently but having a few problems car was parked up for 3 years before I bought it. 1. main problem erratic gear changing auto box checked oil seems fine and puts on the transmission light. 2. when started and warms up the idle is high and stays high in park and neutral making it very difficult to shift from D back to park without slightly going into the reverse gear. the only way the throttle stays at the correct rpm is when it's in D and my foot is on the brake. I plugged it in and got these codes but so iv read on a jaguar forum it could be alot of things causing this anybody any experience with these faults thanks.

 

The XJR has a different transmission then the normally asperated inline 6

You have the GM transmission Vs. the ZF

But the GM transmission is covered by others in this area

Cleaned the connector on the transmission body ?

Do you have the orange dot on the transmission data plate ? there was a upgraded GM design change during the years of production

 

I have a 1996 XJS with the ZF 4HP24 transmission.

I took the car to a mechanic, he couldn't figure it out and recommended I take it to a transmission specialist.

Tranny specialist took it in, and apparently removed the transmission valve body, tested out Solenoid B and told me that it tested perfectly fine, so they recommended I replace the transmission ECU.

Swapped out the tranny ECU, and it made no difference.

I took it to a Jag Specialist and they basically told me that they could go in there, swap out the solenoid (which is either hard to find or NLA) and that it MIGHT resolve the problem, or for a few bucks more, just pay them to swap out the valve body from a jag with the same transmission. (In this case it was a 1997 XJ6) I took the sure thing, he gave me the old valve body back and I haven't had a problem since.

Now I don't know what transmission you have, but you can either source a Solenoid B, and get under the car, drop the pan, remove the valve body, replace the solenoid, put everything back together and see if it works, or you can do what I did and just find a replacement valve body and do the sure thing. You'll have the old one as a spare, and if you want to test it, or try to rebuild it, you can, at your leisure!

 

The transmission has 1 or 2 speed sensor inside that send a sensitive signal to the transmission ECU which cross talks with the engine ECU as they dance together in their regulations

The cheapest try is to clean the transmission connector or look for wire damage close to the area

Someone recently on a XJR had his transmission ECU connector under the glove box ajar not making full pin contacts effecting his high idle speed

The solenoids for this common GM transmission should be easily available and a not too hard to replace

Some of the better designs from a mechanics point of view have the solenoids on the outside of the transmission body

Some of the bone head GM/ FWD designs have you remove the front suspension to be able to remove the whole transmission end plate to get to the solenoids

The solenoid's are rare to see a open meter reading until the solenoid is heated up on the road , just go ahead and replace the solenoid if the easy things don't pan put

Your RWD transmission should be an easy pan removal

Erratic downshifting is a high probability of a shift solenoid windings opening up relaxing to a lower gear

 

Was the car parked outside? Does condensation appear on the inside of the windshield when it's cold out? I'm thinking that high idle may a symptom of an ECU that has gotten wet. If this is possible, have a look at the connectors on top of the ECU box for signs of moisture. It is in the right-hand passenger footwell behind the trim panel that is ahead of the door.

 

The fact she had been parked up for 3 years would seem to offer a clue. Solenoid B may indeed be stuck, as the code suggests, and if it was my car, I would be tempted to change the transmission fluid and drive her for a while to see whether the problem clears.
I would be inclined to think that the high idle is a separate issue, and a very common one on these cars. The long lay up may be the culprit, but in any event, there are copious high idle threads in the forum to steer you through the maze. From experience, I know how difficult they are to drive around town if the idle is even a couple of hundred rpm too high, so you will need to address it. That said, given how difficult the XJR throttle body is to access, a period of some use of the car might help.

 

Hi paddyxjr,

Welcome to the Jaguar Forums! It's great to have you with us.

The first thing I would recommend is that you have your battery tested to confirm that it can provide its full rated Cranking Amps/Cold Cranking Amps. Jaguars are very sensitive to battery power, especially voltage sag during engine cranking. I have a 2003 XJ8 that was triggering a transmission solenoid fault code every time I would start it. I followed the Workshop Manual electrical test procedures but could find no faults. I knew the battery was often low on charge because I don't drive the car often. It was only 2 years old and tested good, but a little under its rated CCA. Just to rule it out, I replaced the battery with a high-quality AGM and the transmission code has not recurred.

Regarding your high idle, my first suspect would be the Idle Air Control Valve. Carbon builds up on the stepper motor pintle and prevents the valve from closing completely, leading to excess air at idle and high idle speeds. An intake air leak or vacuum leak could also cause high idle. We would expect to see lean diagnostic trouble codes such as P0171 / P0174, but these early OBDII systems can sometimes be insensitive and not respond to running conditions that are only slightly out of spec.

Another thing to check would be the supercharger bypass actuator and valve.

You can download the Workshop Manual here:

Jaguar X300 Series Workshop Manual

You can view parts diagrams here:

Jaguar Land Rover Classic Parts

When you get a chance, please visit the New Member Area - Intro a MUST and post a required introduction so we can learn a little about you and your Jaguar and give you a proper welcome.

Cheers,

Don

 

See this thread for more manuals

https://www.jaguarforums.com/forum/x...manual-253724/

 

thanks all for the replies much appreciated i havnt got a chance since to do anything with it but soon I will keep you updated with how I go or what I find thanks.

 

I had a chance over the weekend to spend a hour or 2 on the jag and what iv noticed which I thought was weird was that when I took of the airbox and literally blow air from my mouth into the pipe at the maf sensor the idle came back to down normal rpm while I was blowing. I also noticed that when ticking over there is a slight misfire every now and then so i pulled plugs and they looked near new. but back to the maf I noticed that the unit had no stamp or part number on it and it looked like a aftermarket unit so I got my friends 1996 xj6 not supercharged unit to try to see would it make any difference but no same thing. just wondering could I still have a faulty maf and would a maf cause high idle. im going to spend alot more time this weekend on it and maybe I could post some videos to maybe someone diagnose my issue any info greatly appreciated thanks

 

If you have a supercharged car, and you use a normally aspirated MAF....aren't you expecting to have irregular results?