Hi Guys
New to S Type R.
We have a 2004 which starts and idles but will not rev, gets to about 2K. Seems to be in limp mode and we have a P2135 and
P2118. I think we are looking at moisture near the throttle, but no signs of any. Also possibly an issue on the accelerator pedal? I read issues of the throttle and pedal getting out of sync. Is this easy to resolve? Taken off the throttle body and it seems to have been replaced before as it has XK 4.2 written on it. Would you guys have any pointers to start on? I am thinking start with a hard reset then connect a freshly charged battery and scan again. Any advice welcome.
Thanks in advance.
James

 

You could look up the codes in the jaguar workshop manual and then follow the pinpoint tests to find the fault.

P2135 is generated when the Accelerator pedal position (APP) sensor voltage is not zero at start up.

For P2118 Use throttle body pinpoint test B on page 1419.

One fault could well be caused by the other.

Here is a link to the official workshop manual:

http://www.jagrepair.com/images/AutoRepairPhotos/CarPDFFiles/SType/S-Type%202002.5-2008-FSM-Workshop.pd

Mellow

 

Hi
Thanks for that info. My son and I will get looking into this as soon as it starts to look like we have a dry patch in the weather.
Appreciated. Update later on our findings.
Thanks

 

the throttle body is not too difficult to remove...after taking the windshield cowl off it is easily accesible to take the 4 mount bolts off and pull straight up...the intake pipe is quite easy too...it is pretty straight forward, but the trick is to break the seal free at the throttle body and rubber adapter being careful not to rip it, then pop it up and then pull the pipe off of the mount dowel by pulling towards the radiator....now, the reason to pull the throttle body is to be able to inspect it and see if any carbon has gummed up the works...when i pulled mine on my 06 str for a supercharger exchange, i found a lot of gunk inside and on the butterfly...after cleaning with throttle body cleaner i noticed an immediate change in quicker starts, smoother idle and response....good luck to you...you will really enjoy the car....and we are all here to help....the vast knowledge on the forum, because of experience, is vastly better than just the manual....condolences to the passing of Prince Philip to all in the UK also....hope Her Majesty The Queen is holding up well....she is a once in a millennia person

 

OK here is an update on what I have found. The battery was completely disconnected when doing this.
Pinpoint Test B on page 1419-20. Strangely the test says "THROTTLE ACTUATOR CONTROL MOTOR SUPPLY..." However, the plugs it asks you to measure the resistance on are actually TPS, not the motor.
B1
The resistance between PI26 pin 2 and battery negative = 15.5K
B2
The resistance between PI26 pin 2 and battery positive= 16K
B3
The resistance between PI26 pin 1 and battery negative = 0K - Seems a short circuit.
Just for interest:
B4
The resistance between PI26 pin 1 and battery positive =0.5K and slowly rising. Possibly a capacitor discharging?

Question: Where is PI300? I cannot find it to check the next stages for B5 and B6. Any advice is most welcome. Is that the ECU end?

For now, it seems there is a short on PI26 pin 1 to ground.

Thanks
James

 

The wiring loom/harness looks like it has been messed around with at some point. We suspect at some point when the engine was taken out.
Does anybody have photos of what it should look like?
Thanks

 

If you look at this diagram the PinPoint B instructions tell you to measure the resistance on 1 and 2 to ground and positive. Surely we should be checking 2 and 3? I would have thought the connections we are interested in are the 2 wipers (2 and 3) going to the ECU? Not one of them (2) and one end of both pots (1)?
1 is the common connection at the top of the TPS pots and is connected to PIS48. Engine Harness? But where?
2 is a wiper on the right-hand side of the TPS, it is connected to the ECU.
3 is a wiper on the left-hand side of the TPS, it is connected to the ECU.
4 is the common connection at the bottom of the TPS pots and is connected to PIS41. But where?

Very confusing.
Thanks for any pointers.
James

 

Don't get too far ahead of yourself just yet. As you have already noted, step B3 failed with an apparent short to ground. I wouldn't worry too much about the subsequent steps until you resolve that fault. It wouldn't hurt to read ahead, so to speak, but fix the known faults first.

Wiring diagrams here, see figure 03.5:

http://www.jagrepair.com/images/Auto...x2062004en.pdf


Note connector PI26 (throttle body) near the lower right corner, pin -1, where you recorded the short the ground. That wire appears to be the low side of the voltage ref circuit (5v?) feeding 9 different sensors. Follow pin -1 up on that page and you will see that wire branches out at splice PIS48, and then on to splices PIS47 and PIS49. Unless you find a wire physically damaged and rubbing against metal somewhere, I'd be willing to stake your reputation that one of those 9 sensors is shorted across and creating the fault.

Of those 9 sensors, my hunch is the APP (Accelerator Pedal Position) sensor is the culprit, as it has moving parts. Moving parts are more likely to fail compared to solid-state, so look there first. This would be very easy to check. Unplug the connector (CA88) at the accelerator pedal and see if the short disappears. If so, you'd know how to proceed.

If the APP is not at fault, try unplugging the other 8 one at a time and see if the short clears.

As far the label PI300, yes, that does appear to be at the ECM. There appears to be a disconnect between the connector names on the wiring diagram and the service manual.

 

Wow, that is all great advice. Thanks for that.
What you say makes sense. I will stick to the manual and go step by step, double check the results I already found and move to the APP.
Thanks, I will update you tomorrow.
James

 

Quick question.
Throttle body still off the car.
When reading the resistance of each half of the TPS pots, should they be identical?
As in, should the resistance between 1 and 2 and 1 and 3 be the same at any given position of the throttle plate?
I would have suspected yes. The TPS pots on this one are showing radically different readings.

I have another throttle body off of an X Type, but it has the exact same TPS DENSO 198500-3300.
The TPS on that one responds the same on both sides as the throttle plate opens up to WOT from closed.
I do not plan to put it on yet but suspect the TPS is also a potential issue.

For now, following instructions and will update troubleshooting progress later.
Thanks

 

Working from potentially faulty memory, but I believe the answer is no. IIRC, the two halves operate inversely to each other. This works as a cross-check in case one side acts up and puts out an erroneous value. Let's say the two pots each put out a value between 0-100. Could be ohms, volts, amps, picocuries of radiation, the units don't really matter for this explanation.

With the throttle plate closed:
Sensor A = 0 units. Sensor B = 100. A+B = 100 units.

At half travel:
Sensor A = 50 units. Sensor B = 50. A+B = 100 units.

At full travel:
Sensor A = 100 units. Sensor B = 0. A+B = 100 units.

Pick any degree of opening, such as 37%
Sensor A = 37 units. Sensor B = 63. A+B = 100 units.

How about 43.78% open?
Sensor A = 43.78 units. Sensor B = 56.22. A+B = 100 units.

Note how no matter the throttle position, A+B always equals 100 units. This is the crosscheck feature. If one trim pot was bad, and put out an incorrect value, the two channels will no longer add up to 100 units. You'd get a fault code for at least one channel bad, maybe restricted performance, etc. Even if both channels misbehaved, it would be almost impossible to still add up to 100, so you'd still know something was wrong.

Now I may be out in left field. This may have only been applicable to the APP sensor, I'm not sure, so don't quote me on it. I'm not sure what to tell you about the apparently identical sensor operating differently on another vehicle. Maybe that's not a part number, but an inspection stamp or something like that? Or it could be a part number for the housing only, but the innards are different.

What kind of meter are you using? I've got about a dozen different models, but my Fluke 83 is my go-to. If you want to take it from me, you'll have to pry it from my cold, dead hands. But for checking a trim pot, a digital meter is not the best choice, even with the bar graph across the bottom of the screen. It's just too sensitive, and it's difficult to observe a small dead spot in a trim pot as the numbers go up and down. An old-fashioned analog meter, such as my Simpson 260 is ideal for this. The needle will react quickly and a fault is easy to catch.

So I'd suggest measuring each channel independently and see if the two operate inversely to each other. If so, make sure the output values change smoothly as the sensor moves through its range. If inconclusive, can you rob the sensor from the other vehicle for troubleshooting?

 

Hi Karl
Thanks again.

I thought I had replied to this but maybe did not submit.
The cross-check makes sense.

I am using 2 different digital meters (just average ones) But I have a couple of old AVO8s which I may be able to check it on.
Interestingly the pot on one side is measuring twice the value of resistance of the other. The same part TPS from the other car does not, they are the same value.
I wonder if I have a bad track on the suspect one. I can swap and see what happens, First I waiting for some 5 point torx bits, which I cannot find anywhere.
However, I still need to continue fault finding on the short. That is the plan for today if it stays dry.

Cheers

 

OK here is a general update.
We changed the TPS as it was behaving in a suspect manner from my near 40 years studying and working on electronics.
New Yuasa 019 battery on there too.
Problem is gone. Engine light off. No fault codes, limp mode gone. The engine now revs freely up to 3K (not tried more).
I am not sure where the Pinpoint test was taking me in the workshop manual but I suspected a disconnect when it started referencing fault finding on the throttle motor and then instantly referred me to the TPS connector.
Maybe there is still a problem there (possibly a short on the part of the TPS pot I am surprised it was asking me to test), but the fault has gone.

For now on to other faults.
Its miss firing very occasionally. Possibly old plugs, possibly 2-year-old fuel. One of the coil packs is different from all the others, possibly that........?
The brakes are really really spongy, possibly old brake fluid that needs changing.
We know we need new discs, probably pads.
The transmission lurches going into drive and reverse. Forum searching it seems is a common fault that may be (hopefully) cleared by resetting the transmission adaptations.
But on the whole promising for a car that has sat for 3 years doing nothing.
Need to get a replacement locking wheel nut key.

I will start a new thread on these other points if we get stuck and if we fix it and move on I will post the problem and how we went about correcting it.
Thanks for all the help, explanations, and encouragement.
James

 

Forget the trans until you've fixed everything engine-related because engine faults can really upset the trans.

Don't rev 3000+ when parked - engine should limit and cause what feel like misfires. It's protecting things from the damage such revs can cause.

 

Stellar work, glad to hear you got the problem sorted out. It's so easy to panic when one gets some obscure fault code, but the root cause is usually something simple.


i shared your same doubts about those pinpoint tests. Usually they are are very specific, and live up to their name. But for whatever reason, that group of tests was quite vague. Not sure what was going on there. Maybe an inexperienced engineer wrote those tests, who knows?

As previously mentioned, don't rev an unloaded engine very high. With no load on the engine, it's very tough on the connecting rods and wrist pins.

 

Thanks guys.

When testing the revs I knew it stopped at just about 2K so the rev was simply a blip to see if it went over, I saw it hit about3K a couple of attempts.
The idle also now behaves as in the revs go up to something like 1200 to start then drop back to around 800. Roughly. It was not doing that before and staying over 1K.
The misfire happens on idle too, so I am going to check the plugs and maybe clean or replace them. Some nice fresh high octane fuel.Then look at that odd coil pack.

Gradually getting there.
Thanks

 

Have you driven the car much since awaking it from hibernation? Minor misfires may not get flagged right away. I'm thinking if you log a few spirited drive cycles, you might get a misfire code specific to one cylinder. Then you'd know where to look first.

That new coil? It may be a recent replacement and the others are original. Could be the previous owner fixed an obvious misfire by replacing one failed coil. However there was a second minor issue with another cylinder, but he never got around to that. Basically, don't paint yourself into a corner thinking the present issue is caused by the one oddball coil. It could be the best of them all, and one of the other originals is at fault.

I'd also recommend some spirited driving for another reason. After sitting so long, some valves or piston rings may be sticking and causing low compression. Work the engine hard and they might just break themselves free. A misfire code merely means low power output from a particular cylinder, not just an ignition problem. I've fixed a few dormant engines with a good (insert name of ethnic group) tune-up.

Almost forgot, here's an easy procedure to calibrate a throttle position sensor:

https://www.jaguarforums.com/forum/s...ection-176446/

 

Hi

We have only had the car a week or so, the previous owner bought it about 3 years ago with the intention of it being a small project for him. His personal circumstances changed and he could not manage to find the time to do anything at all with it. Now 3 years later we come along.

In the UK we are not allowed to drive on a public road until the car passes a basic government test for "general roadworthiness". So I have not driven it yet, other than about 10 feet on the driveway. The brakes are a must to fix before I can book it for a test and therefore take it out. But worried about the transmission lurching. It really jerks into movement quire ferocious. I found this site which seems to be dedicated to the issue. Jaguar S-Type ZF Gearbox Lurch fault

I was thinking of leaving the misfire until a code shows up. But I guess it will not hurt to look at the plugs for a health check.

Thanks for the reset link. I had actually found that one and read it the other day, but now I am reminded to do the procedure before taking it out.

.

 

Ignore the trans for now as it is probably being upset by the misfires etc.

If you let the car warm up fully at least twice it has the chance to set codes and it may be able to tell you which cylinder(s) is/are problematic.