I figure I would start a new thread on this since I have more information and someone would find it easier to search. So it looks like this does not come around that often. I looked at the TC actuator and replaced the electrical cables between the actuator and the plug and I thought that this fixed the code. Went out for a trip and it came back again in the maintenance tool but the light did not come on. Turned off the car reset it and drove again. hit the 12.5 MPH and there it was again. I went ahead and sent off the ABS module for repair, even though that had nothing to do with it. Are there any other suggestions? Parker 7 gave me a list of things to do with no resolution. I did replace the Actuator off of another car because my good old plastic was broken. I guess that could be it. Just not sure what else to do.

 

The DTC is faulting the position sensor on top of the actuator assy.
It looks like a Throttle Position Sensor but it is located on the motor/cable unit.
Maybe the calibration is WAY OUT on the cables?

 

0.47 volts DC with the TC on or powered up according to the break out sheets before the actual TC / ABS schematic page

This would be a null or neutral position before it retracts

To fully test the TC actuator you would have to trigger the actuator to retract and watch the signal to be smooth and no open on the rotary variable resistor as that is all it is

On aircraft we would spin up one wheel sensor to trigger the anti skid system to trigger and actuate in this case releasing the other brakes

But in this case in a TC if you spin one of the rear wheels in the proper fwd direction you are simulating one wheel spinning faster then the other side and trigger a response in theory unless there is a whole car speed limitation

You have probably opened up the cable wrapped around the top cable bellcrank , if so you can just manually rotate the sensor and test it by resistance on a meter

But it would be easier to lube the throttle cable crossing over to the mounting position on the left of the engine

There are 2 positions marked on the left side cable fixing bracket that may be not able to read as A and T or A and M

 

I am sure that is what it is. I replaced mine. Now the question is how to calibrate it

 

"You have probably opened up the cable wrapped around the top cable bellcrank , if so you can just manually rotate the sensor and test it by resistance on a meter" Can you show me where that is?

 

If you have already installed the assembly, You can turn it on and the actuator should come to a mechanical null different then a electrical null on the Blue colored wire as you have everything hooked up

You would have to nick the wire

In a shop setting there would be a insert made up test connection between the 2 factory connections

0.47 volts DC on the Blue color wire

Editing

Most likely you will not be able to get it to actuate by spinning one of the rear tires as there is a low speed inhibit and we had this on aircraft for some forgotten reason, but this was in a anti - skid mode




See video , this is when **** gets real on a real test flight , The Captain later died as a flight instuctor

 

He literally pulled t out of his a$$. So with the car running, that is what I should get off the wire. If I don't then what.....PUNT? And that wire is coming from the connector attached to the actuator?

 

What I. noticed today, and I think it has been there since I changed out the actuator, is we all know when we usually let off the gas while moving pretty well, the car slows down because of the high compression. Well, with the change out of the actuator it now takes a while before it starts to slow down. Kind of like the cruise is on. So I assume that this is my problem and I somehow need to adjust this or recalibrate. So, am I right that the two bolts on top loosens and you can turn the connector to fix that?

 

There was a car here in KC that I only got a faint verbal on was by removing the connector to the TC actuator he was able to regain his idle

I wasn't there so I couldn't nail down exactly what went on but the waste of an individual eventually lost his Jag when he got it towed and scraped after a friend left it behind in a Casino

He initially bought the car with a bag of drugs and he was a dandy to square up but never did

In your case you are out of the idle region and in a natural throttle let down similar to a commanded transmission kick down but different

You can isolate the TC system from the rest of the main throttle cable and see if the issue remains

Not all X300s have the TC option

The high rotating mass of the long stroke engine may supersede the compression resistance thought

This rotating mass inertia would be higher on a big crankshaft truck engine which is what you have then a V8 or V6

 

I know that the actuator is the cause since it was not there before I swapped it out. I guess my next steps are either to find another complete actuator or take it to jag to let them figure it out. Since I ha e the day off tomorrow I may give it a shot to see if there is any way to make adjustments. I wish I had a real repair manual or a TSB for this. I kmow that +xjrengineer might be able to help since I have seen a few posts from him that sounded like he may know something.

 

With the TC switched off does that make any difference on your observed throttle let off

You may have an issue with the IAC valve not scheduling down in the correct fashion

It might not be scheduling closed in a fast enough clip because one of the windings may be open not allowing the valve to move or close down on a step ( and stay wide open )

In your final let off the throttle state of the engine at idle you may have a set of IAC windings that are good and you have the correct IAC valve position

But you did say you didn't notice a change in the throttle let off until you changed the TC actuator

I am assuming the TC actuator is not firing off by retracting seeing a rear wheel spin and the In action light on the dash vs. a inop system fault light

Throttle return spring ( lacking in enough retraction force ) addressed by the TSB ?

 

Since I have the day off I will be working on it tomorrow. Probably going to take everything apart and start over. Maybe I have something too tight or I might play around with the adjustment on the top of the actuator. I will be pissing in the wind but I can't hurt it more than what it is now. I will check the voltage on the blue wire for the heck of it if I can find which one it is.

I know I also have to replace my sport and automatic switch since it does not work anymore. I think that I also replaced it but can't remember.

Also kind of weird that there is no talk anywhere about that adjustment. I know it does something just not sure what. I have one I took apart and it does do something

 

on the sensor wires one will be 5.0 volts DC reference voltage and another will be a ground and the 3rd the 0.47 volts

So you know look for volts first

 

See post # 31

Gearbox light, idle problems - Page 2 - Jaguar Forums - Jaguar Enthusiasts Forum

 

This document is very handy. However, I sure would like the document that this came from. It seems like some type of mechanics document. All the manuals I have, which I have, I don't see this one

 

There is a summary of all the systems in the publication XJ Sedan 95MY Intro_jjm10151250.
The publication .pdf is over 13mb so will probably not upload to this forum.
Gus should have it on his site. I sent him hundreds of documents.

 

What site is that. Could I have a link plz.Found it

 

After spending a day following the document above I think, driving it for 15 minutes and no faults (I used to get them just going down the str) I have finally resolved my Traction control. I will take it on a long journey later to see if it stays away. However, I did find a few things. A while back I had replaced my actuator cables because of the broken plastic pieces. I pulled them off a 96 XJ6 and for some reason, the cable was about an inch shorter which was putting some stress on the actuator. According to the document, there should be a way to make an adjustment to the cable that goes to the throttle body. That cable does not exist at least from the two that I had. I had to make a few modifications so that the cable would actually reach and not keep the idle too high.

So for now, I have
1. Resolved my Tra fault
2. Resolved my gas gauge problem (replaced the float)
3. Not sure about my airbag problem. Yesterday it would come and go but after pulling out my entire console to change out my linear switch everything SMS fine. Must have been a ground problem?

Last thing I need to fix is the Sport Mode switch. Getting power to the switch but it does not do anything

 

Well I thought I had it fixed but it came back. Now after pulling my cluster and my console my airbag light won't turn off. It has to be a ground problem. I can't figure out where it grounds to

 

Can someone tell me if the position sensor should be touching the actuator pin. After making adjustments to the throttle cable and the actuator the airbag light is gone which makes no sense