Also it will not manually shift.

 

OK, the Check Engine Light (CEL) is on - that's important.

Is the transmission warning lamp illuminated? I know I've asked three times, but you haven't answered...

You can check the Diagnostic Trouble Code(s) (DTCs) causing the CEL by following this procedure:

Turn the key to position II (ON/RUN) but do not crank the engine;

Press and release the VCM button on the trip computer to the right of the steering wheel;

Watch the small display window where the odometer normally appears for a message. DTCs appear in the form of FF or Fuel Fault plus a two-digit number, such as FF23 or Fuel Fault 69. Write down the code exactly as it appears and post it hear and we'll try to help.

Cheers,

Don

 

No transmission bulb is on

 

So what fault code do you have displayed when you press the VCM?

Larry

 

Ok,last owner took bulbs out,Trans light on also bulb failure light on.I cleared codes so won't be back on for a couple of days.

 

We'll try to help when you can read the codes.

 

Larry I have a off question for you, my bulb failure light is on on the dash all of my lights work except for the fog lights are the fog lights actually attached to that bulb failure system?

 

Yes they are on my car (94MY) but check your numberplate lights too OK

 

Fuel fail 23

 

Real quick question, what is with the computer hard restart how do you do that?

 

Hi Thumprr1226,

First of all, please use your User Control Panel (User CP) to edit your signature and add your Jag model, year, engine and mileage so we don't always have to scroll back to your first posts for this information. The model year and engine of an XJ40 can make a significant difference in the correct answer to your questions.

Fuel Fail 23 indicates that the oxygen sensor is showing rich running that cannot be corrected by the Engine Control Module (ECM). This can be caused by a number of issues, such as high fuel pressure, a failing coolant thermostat, a stuck-open purge valve, a failing oxygen sensor, etc. Follow the diagnostic flow chart in the manual at the link below:

Jaguar AJ6 Engine Management System OBDI / Diagnostic Guide


Another document to have in your library is the Haynes manual. You can download a scan of the U.K. edition at the link below (it's missing a couple of chapters but is otherwise complete):

Haynes Jaguar XJ40 Repair Manual

Regarding a hard reset, one method is this:

With the key not in the ignition lock barrel, disconnect the battery negative cable;

Wait 10 minutes;

Touch the negative cable terminal to the positive battery cable terminal and hold for 2 minutes.

Reconnect the negative cable to the battery.

Note that you do not need to disconnect the positive cable from the battery - touching the negative and positive cable terminals leaves the battery out of the circuit.

Cheers,

Don

 

So is the transmission shifing issue a way of forcing you to fix what's going on with the engine codes first

 

FF23 has nothing to do with your tranny problem, although one of the possible causes of an FF23 is a bad connection or ground at one of the sensors; possibly a similar bad connection *somewhere* is also contributing to your limp home mode issue?

ps - follow Don's advice/method and add your car details to your signature, OK

Larry

 

Can either one of you tell me where that vacuum line goes to under the battery box in my 91 sovereign

 

There's a good chance that's the battery vent line - it's supposed to connect to a port on the end of the battery and carry acidic fumes down under the car where they will be dispersed by moving air when the car is in motion.

Cheers,

Don

 

Yours should be an electronic unit, these have solenoids to control trans operation and an ECU located in the passenger foot well. They also have a decoder unit to decode the signals from the rotary switch in the shifter. Any issues with these components such as dirty switch contacts, bad wiring connections, broken wires, faulty sensors, or a failure or the ECU will case issues. The fact that it won't switch into sport mode suggests an electronic problem to me rather than a mechanical issue in the trans itself.
Every issue I've had with electronic auto units has been with the shifter switch (mostly), wiring connections, or in one case faulty capacitors in the ECU.

If you have a manual you need to work through the components one by one and check all the connectors, including the plug on the ECU. Most of the time I just pull the connections apart and give them a squirt of cleaner, but you can get corrosion and this can be scraped off gently with a small screwdriver.
If you can try to borrow a shifter switch and ECU off a wreck so you can use them for fault finding.

I have only had the hydraulics fail on one or two autos, these days the great majority of problems I have with my cars is with the electronics and associated wiring.

Hope this gives you some ideas.

 

Going to be a long weekend.thank you.

 

Jon Ping wrote an excellent diagnostic routine for the ZF 4HP24 which is part of the Jag-Lovers XJ40 eBook. It has worked for me every time I've needed it:

Jag-lovers' Ebooks

Among the photo albums at the link in my signature are albums on the rotary switch, decoder module, transmission electrical connector, Throttle Position Sensor (TPS), and Transmission Control Module ((TCM) solder joints are known to fail).

Cheers,

Don

 

Don I just have a real quick question is the transmission relay supposed to click or hum at all, because it is doing nothing

 

A good working relay should click when it is engergized or de-energized, but should otherwise be dead quiet in either state. A relay that hums is not healthy or is not receiving a clean or adequate DC control voltage.

You can easily test a relay by connecting your ohmmeter to terminals 30 and 87 with your meter set to the lowest resistance scale (typically 200 ohms unless your meter is auto-ranging).

Connect alligator-clip test leads to terminals 85 and 86. When you touch the other ends of the leads to the terminals of a 9V battery or the 12V battery in your car, the relay should click and your ohmmeter should change from infinite resistance to zero ohms (or close to zero since your test leads will have some resistance).

You can also test the power supply to the transmission relay. There should be battery voltage (B+) present between terminal 30 of the socket and ground at all times. With the ignition switched on, there should be B+ voltage present between terminal 86 and ground.

Just to confirm the relay you're examining, the transmission relay has a purple base and is clipped to the right blower motor housing behind the glove box.

And again I ask that you please use your User Control Panel to add the year, model and engine info of your Jaguar to your signature line. Once again I had to go back to your first post to find the year of your XJ40. It really does make a significant difference in giving you correct replies, so please help us help you by making our (volunteer) lives a little easier.

Cheers,

Don