Hey, all! So I'm trying to trace down an issue that's been kicking my car into Restricted Performance mode. When the car kicked into Restricted Performance mode, it threw the following codes:

• P2105-00: Throttle actuator control system - forced engine shutdown.
• P061A-29: Internal control module torque performance - signal invalid
• P061A-00: Internal control module torque performance - no sub type information
• P2135-00: Throttle/pedal position sensor/switch A/B voltage correlation.

From what I've read, it's very likely to be the battery - I'm working on getting a new one in - but in the meantime, it's raised a few questions for me...

1. Absolute throttle position: This value never exceeded 49.8% during a WOT pull - is that normal?
2. Accelerator pedal position sensor - Circuit E: This value was 14.9% at steady state idle. The PID info for this (PID F44A) says that typical idle value is 7.45%, with a lower limit of 6% and an upper limit of 9%. Does the idle value of 14.9% indicate that some type of adaptation is required, and if so, how would I go about doing that?
3. Pedal and throttle position sensor voltages: (there were 4 separate values I recorded at idle):
   1. Pedal position sensor voltage - sensor 1: -31.23 v
   2. Pedal position sensor voltage - sensor 2: -31.61 v
   3. Throttle position sensor voltage - sensor 1: -31.55 v
   4. Throttle position sensor voltage - sensor 1: -30.49 v
   5. From everything I've read, those voltages are way out of spec - is that right, or do I have the wrong information? Does anybody have the part number for just the TPS, instead of the entire throttle body assembly?

I have the freeze frame data for each of the codes that were thrown, if any of that is useful information. I'm coming from Audi, so most of my experience with datalogging is via a Cobb AccessPort 3 - a little different than the Autel AP200 dongle I've been using with the Jag.

 

Bump.

TL;DR is basically this: Does anybody know the normal voltage range for the pedal and throttle position sensors? Barring that, does anybody know what the normal throttle and pedal position values are at idle and WOT?

 

Looks like your tool reports some values wrongly. Better tool needed...

 

These results were consistent with an Autel AP200 (which seems to be highly recommended in Jaguar circles) and a Foxwell NT710.

 

Try this:
Replace your battery.
Make sure your new battery is fully charged.
Clear all the old DTCs.
Take a 20 minute drive. Any check engine light?
Scan for DTCs.

If no new DTCs, it appears that your previous DTCs were caused by a low battery.

 

So I did get around to replacing the battery, and everything was good for a few days... then the same issue occurred again: the car stumbled a few times while cruising at ~55 MPH, then kicked itself into restricted performance.

I didn't have either tool with me, but after letting the car rest for a few minutes, restarting it (started up first crank), and driving about a half mile, the restricted performance alert cleared and the car drove perfectly fine back home. I'll have to pull the codes later tonight and see what threw it into restricted performance, though I assume it's the same issue as before.

 

If I had this, I'd check the throttle position sensors.

 

Yeah, I think that's the next step. It's either that or the accelerator pedal, IMO.

Whatever it is, it's getting worse: the car kicked into restricted performance 3-4 times today, and where in the past it seemed to recover pretty cleanly after being allowed to set double-locked for a few minutes, it persisted after multiple restarts and battery resets.

Strangely (and perhaps completely unrelated to the problem), the final time it recovered from restricted performance mode was after I depressed the pedal about 50 times (with the car off) before starting it. My thought with trying this was that, if there's an issue with the potentiometer contacts on the pedal, maybe wiping the contacts a bunch of times by pressing the pedal repeatedly would ameliorate things. Maybe it's worth noting that it's been unseasonably humid the past few days, as well - who knows?

Anyway, when the car is in restricted performance, it runs extremely roughly: lopes almost like a cammed V8, idles low, struggles to find idle, and responds very erratically to throttle input (slowly revs up, revs hang, then revs slowly drop). Obviously when it's coming up I'm pulling over and turning the car off as soon as its safe, but I get a sense of how its idling when restarting the car and giving it a few seconds to see if it's able to pull itself out of that mode. Here's a snapshot of the codes thrown when the car entered into restricted performance today:



Actually, now that I think of it, I noticed some strange behavior when trying to start the car after it went into restricted performance: there were a few times that the car wouldn't start at all. I'd depress the brake (stomped - firmly depressed down to the floor), press the ignition button, and nothing would happen but the screens going mostly blank (the information center screen kept the PRNDL display, so it was still receiving power). No starter sound, no clicks - no attempt to turn over at all. Just the click of the infotainment turning off, then silence, almost like the car turned off. A subsequent press of the ignition button would seemingly put the car back into accessory mode, again almost like trying to start the car had actually turned it off. Once the battery was briefly disconnected and reconnected, the car started right up with no issue.

This is with a brand new battery, testing fine, that's been on a battery tender every night just to be sure.

I'm stumped! I've got freeze frame data I can share if anybody thinks they can make sense of that. Aside from the strange voltage readings I shared in the OP, nothing else there has really stood out to me, but this is a new platform to me so maybe I'm missing something...

 

They mystery continues.

After leaving the (new) battery on a tender for about two days, the car drove fine for a day - no restricted performance, no weird behavior, no nothing. There was a CEL for the first 15 or so miles that I drove the car, but it seemed to clear. Every time I started the car, though, I'd be presented with a "Service Required" message. I figured there were probably some DTCs that needed cleared, so I hooked up my Foxwell NT710, read the modules, and cleared the codes. Ignition off, ignition on, brake depressed, try to start the car and... nothing. No whirring, no cranking, no nothing: it's just like I pressed the ignition again to turn the car off.

The car remains in this state (trying to start the car just turns it off) until you disconnect the battery and reset the car - then it starts right up.

So basically, if I clear the DTCs, the car won't start until the battery is disconnected and reconnected. This has nothing to do with the health of the battery: it's a brand new, fully charged battery.

Okay, so now the car has been reset. It starts, but the idle is rough and it eventually stalls. After the stall there's a strong smell of gas, almost like the engine was flooded or running rich. A few more starts and stalls, and the car finally idles. At this point I'm trying to do the relearn process (start, idle until operating temp, car off, car on, idle 2 minutes, shift into drive with foot on brake, idle 2 more minutes, drive 5 miles). I put the car in drive, it bucks a bit, and immediately kicks into restricted performance again. Here are the codes that are preset at that point:



So I mean, at this point, so I just start replacing parts? Apparently I can't trust the Foxwell NT710 readings for the pedal and throttle position sensors, and nobody knows what the normal voltage ranges for those sensors are, so what good does it even do to probe them? The DTCs seem to be pointing to the issue being related to the accelerator pedal position sensor and/or the throttle position sensors. The APP is easy enough to replace - looks like a $200 part behind a few screws - but from what I can find in the workshop manual, the throttle body and TP sensors are sold as a complete ~$1000 assembly.

And what the hell is going on with the car refusing to start after clearing DTCs? Related to the APP/TP sensor issue, or a red herring?

Such a beautiful car, but these issues sure are putting a damper on the fun.

 

Just thinking aloud... after battery off the fuel trims and other learning are all gone so it will start a bit like with a choke: i.e. rich, OL (open loop), trying to get warm enough to go CL (closed loop). A stall may well result in you smelling petrol.

Cause of stall? Any sensor that misleads the PCM enough or of course an air leak can do it.

Main things it relies on when starting will include ECT, IAT, MAF. I suppose TPS/APP. Fuel injectors. Coils & plugs. Bound to be battery both voltage & current. A fair few relays, fuses, wiring.

You can ignore a lot of things above, I expect, as they're "known working" (hopefully).

 

Thanks for the tips! That explanation makes sense regarding the smell of fuel. It drove fine today, as it were.

I'm going smoke test it and see if I can't find an air leak. All of the DTCs I've seen call out the TPS/APP, so I'll probably pop out the pedal assembly and see if I can't get to the potentiometer tracks and see if they need cleaned, along with checking the connectors. The TPS appears to have two connectors from the harness running to it - I'll check those as well. I've read a few posts that pointed to poor contact with those connectors causing issues.

I wish someone knew the normal voltage ranges fro the TPS/APP. I haven't been able to find any info on that online or in the workshop manual.

 

Any luck isomorphzeta?

 

Smoke test passed - I wasn't able to identify any vacuum leaks.

I ordered a replacement accelerator pedal assembly and will try replacing that. At the moment, I'm letting my independent shop take a look at it to see if they can identify anything obvious that I'm missing. I had to have it in there to have the dampers replaced anyway, so I figured I'd let them take a look at this mess as well.

 

Just to follow up, for those that may have an issue like this in the future: my issue was related to the throttle body. Replacing the throttle body assembly and connectors seems to have resolved the issue with the car going into Restricted Performance.

I haven't thrown the Foxwell NT710 back on to pull the codes and check the voltages, but things have been stable for the past 2 weeks.