Ok, so I am idiot and bought another STR. This one won't start. Luckily I have one that does start and run, so I was thinking that would be troubleshooting easier. It only shows one code, a P0121 throttle body code. Previous owner had it running and driving and it wouldn't start after a fill up at a gas station.

Car has a brand new battery and I have it on a charge to make sure it is charged. Car shows normal fuel pressure with key on and when cranking.

My normal routine with runnning/non-running pairs is to swap parts between them until I find the offending sensor or device. So far I have swapped the CPS and the fuel pressure sensor.

I have ohmed out the TPS connector to the ECU, all wires check out good at 1.5 ohms. I tried to check the sensor resistance from the sensor wire to the ground and input voltage references, but both TP1 and TP2 show no continuity with the throttle closed. I searched for threads where someone ohmed out the sensors but could not find one. I am reluctant to swap the throttle with the running car because of how brittle the connectors are and I have read the horror stories on getting replacements. I was thinking of swapping the MAF over but no code on that.

I am wondering where to go next with relatively low risk. I'm pretty familiar with similar year LR's but they are simple compared to this. On those it basically comes down to CPS or security system lockout.

 

Hi Extinct,
Not sure if this helps you but I think the TPS in your vehicle is similar if not the same as on the later throttle bodies of the 2.5 & 3.0 used in the X-Type. If so you should be able to replace just the TPS.
I found this info which I hope is relevant to you if you are trying to resistance check your TPS.
Related DTCs
P0121 Throttle sensor circuit 1 and 2 range/performance.
P0122 Throttle sensor circuit 1 low input. P0123 Throttle sensor circuit 1 high input.
P0222 Throttle sensor circuit 2 low input. P0223 Throttle sensor circuit 2 high input.Using a Digital Multi Meter (DMM) carry out resistance checks across the sensor Throttle position sensor, track 1 Between EN013 pin 1 and pin 3, Resistance when throttle closed = 0.5 k-ohms - 0.9 k-ohms. Resistance when throttle fully open = 2.0 k-ohms - 2.4 k-ohms. Throttle position sensor, track 2 Between EN013 pin 1 and pin 2, Resistance when throttle closed = 1.2 k-ohms - 1.6 k-ohms. Resistance when throttle fully open = 2.1 k-ohms - 2.5 k-ohms. As the values increase and decrease, pay attention to any display of an Open Circuit (O/C), this will indicate a potential fault on the track.
As for the connector a similar discussion was just had over the fence in the X-Type forum which might be relevant for you. Link below:-https://www.jaguarforums.com/forum/x-type-x400-14/help-electrical-connectors-couple-other-issues-249688/

Why the fault has manifested itself when the prior owner filled up is anyone's guess. Perhaps he also happened to put the car through a car wash or gave it a power wash which seems to be a issue for inviting the TPS to possibly receive a deluge from the water draining onto it from a mounting hole in the cowl panel. There is a VIN specific technical bulletin S303-S159 which outlines that scenario.
Good luck.

 

Thanks Mark, I couldn't get any resistance ready on the pins for the TPS, which I found unusual because the tracks should have some resistance because it is basically a rheostat. I have to think if I want to swap in the throttle from my other car. Kind of surprised that a TPS code would prevent starting. I have verified 55psi cranking fuel pressure, and I can smell gas at the back of the car. I am assuming a security immobilization would give a code on the dash, I have none. Wondering if this TPS error woudl turn off the coils.

 

Hi Extinct,
I agree, the TPS should always give you resistance readings as you are correct it is a rheostat, not of an optical encoder type.
It may well inhibit coils....it the ECM doesn't know where the throttle is, to the point that the throttle body is missing as far as it is concerned, it is likely going to have a **** fit!
It is trying to rationalize and reconcile the pedal position to the throttle position, if half the equation is missing it is likely to not know how to move forward and err on the side of caution and not let engine fire at all.

Not sure if the immobilizer stops cranking altogether or just inhibits spark production.........seems logical to stop the starter cranking altogether along with killing spark.
If you have a RFID error the ECM won't engage starter permission typically.

Can you manually advance the throttle butterfly to move the TPS off the current possible dead spot?
You might find you then get some readings from the wipers to at least one end of the fixed resistors.
If nothing the TPS must be corroded inside.

 

If the immo trips you get a code via the PATS light.

I don't believe the TB / TPS can cause that i.e. you seem to be looking at the wrong item(s).

Of course if (say) the air flow as measured is wildly wrong then the car will add the wrong fuel and may not start.

 

Working from potentially faulty memory, I think the security system has different responses for different scenarios.

In some situations, it only inhibits the injectors, but lets the starter engage normally. I think the logic is to let a thief think he’s making progress but the engine will never run. But in the meantime, he can try and try until he kills the battery.

In other scenarios, the injectors and starter are all inhibited.

I do not remember the logic for the different responses. I think you can find the information in the training guides at Jagrepair.com.

 

Mark, the local junkyard has an X-type, was thinking of trying the throttle body off of it, do you have a source where I can research the X type to see if they are the same? Do you know what years? I would be kinda surprised given the airflow needs of the 4.2SC vs a 2.5

 

Look up the part #s.

 

Hi Extinct,
Sorry for the delayed response....half way around the world from you ;-)

Yes I would assume the physical throttle bodies will be different between the 2.5/3.0 and 4.2 displacements, but I believe the TPS mounted on them is likely the same.
On the X-Type there seems to have been a production change where the throttle body was replaced and subsequently the TPS used was physically different.
Here is a thread from over the fence that might help.
It shows the two TPS variants, the larger unit as seen on the throttle body. I suspect you may have the smaller TPS module shown.

To save you some reading, scroll down to post #58, as that is where the TPS started being discussed in earnest.
This thread is on a 'no start' X-Type which is intermittently no crank also, but the thread goes on quite a journey and S and X models can have some cross pollination of parts which is why as a newer member I tend to read threads on both models.

https://www.jaguarforums.com/forum/x...-246481/page4/

Good luck

 

Hi Extinct, I've had the P0121 code for the TB twice before on an 02 STR (I had a bad TPS & changed the TB for a used item that lasted a month ! Then I bought a new one).
The car had no problems firing up but would idle at about 1500 rpm. It would also run because of the high idle but obviously quite slowly, so at least I could move it. The other thing that is shown is 'Engine Systems Fault' on the dash display. If your car isn't starting, I doubt it's the TB/TPS. Sounds like something else has failed. Do you have any Freeze Frame data for the DTC ?

 

Well I swapped in the TB from my other car today, eliminated the code but still no start. My JLR tech friend and I both think it is immobilized. I have been resistant to getting the IDS software and all the BS that comes with it, but it looks like my choices are now either tow it to the shop an hour away, get the software and turn it off, or sell it as it. Gonna call the shop tomorrow and see how backed up they are.

 

Is the PATS indicator light flashing a code? I'm pretty sure the light would indicate a fault if the security system had immobilized the car.

Have you verified the presence of spark? I vaguely remember something like the crankshaft position sensor (CKP) can fail and kill the ignition. However, it won't set an OBD code because a failure to start is not an emissions fault.

 

Pats is not flashing a code. I have swapped CPS with my other R and confirmed it is good. I am thinking either immobilized or bad ECU at this point. I have 55psi cranking fuel pressure, and can smell fuel at the rear of the car. Car does not even pop.

 

Once again, I'm almost positive you'd have a PATS code present if immobilized.

From your description, it sounds like you have no ignition. But have you actually tested yet for the presence or absence of spark?

If no spark, there are LOTS of possible causes. Yep, the security system could have disabled the ignition, but the symptoms don't match (no PATS code) and there are plenty of other possibilities. For example, the ignition circuit has a control relay and two fuses. A failure of any item could kill all ignition. There's also a capacitor and diode, all prone to failure. You can easily test if the coils are receiving battery power. It's a little trickier to test for the switched ground that tells each coil when to fire. But testing the supply side is a piece of cake.

All I'm trying to get at, in the kindest and gentlest manner possible, is not to paint yourself into a corner while troubleshooting. Go where the clues lead you, versus trying to confirm your hunch. Things can get expensive when you do. I do not care to discuss how I know this.

 

Agree with Karl. The PATS will flash that little red light if there is a problem.

Good idea to hook up the SDD and see if any PATS stuff shows up. First spray starting fluid into the intake and crank the engine. Does it run or try to run?
If nothing then we are back to spark. Can you test if the plugs are firing?
.
.
.

 

Thanks guys, you were spot on. Blown ignition fuse. Now I just need to fix the P1229. I looked up the part numbers on the X type and the S type R, seems some part numbers are the same and some are not. Probably the same basic unit, just a difference in the coolant lines? Anyone have any tips?

 

Fantastic, glad to hear you've got the ignition working again.

One bit of important forum protocol, though. There's no need to post anything confirming I was correct. It's just a given around here. If there was such a reply every time I was correct (basically any time I post), this would cause serious bandwidth constraints and drastically bog down the entire internet.


Is this a new code? I didn't see any previous mention of this code in your thread. If new, it's good to narrow down when it started, such as right after some part was replaced.

 

Yeah, new code when I swapped over the TB. I am pretty sure it is because the connector is gone. It disintegrated when I touched it. Shoved the wires in the TB but they probably vibrated out as soon as it started.

 

Got a connector off of a V6 car, same connector. Car is driving. Now has a knock sensor code, and seems like its missing pretty bad on a couple cylinders. Going to try swapping some coils, check the knock sensor wiring.

 

https://youtube.com/watch?v=OWwOJlOI1nU

Careful! New symptoms appearing immediately after other recent work? That's usually means you need to review what was just done. Could be a connector not fully seated, wires spliced wrong, defective replacement parts, etc. I highly doubt a coil or knock sensor suddenly failed out of the blue at the same time.