01 XJR with 169,000 miles. Had PPS problems with my original throttle body, finally bought the remanufacture service from ASI, ended up with a completely different TB off the shelf. Got it installed and all is well back in January/February of this year. I did get an engine failsafe mode issue right off the bat, ASI recommended doing another hard reset which seemed to address it. Fast forward to mid August and I go into failsafe mode again, this time with a MIL indicating code P1122 (TPS circuit intermittent low voltage). I pulled the connector, cleaned it with spray electrical contact cleaner and the TPS side, let it dry and reconnected, did a hard reset and all is well. Until Tuesday when it went into failsafe mode again. I pulled over, restarted, seemed ok, drove another 10-12 miles and it did it again with a MIL, which returned P1122 again. Did a hard reset and drove to work and then later drove home without further incident, but car is parked now and I'm using my backup until I figure it out.

I've contacted ASI for assistance, waiting on a return call.

I believe my car has had the TSB 303-58 applied to it, the car side connector looks to have gold colored connectors inside the plug and the covering for the wires is missing, so I'm guessing this has been done before I bought it.

Apart from a replacement TPS, are there things I should be looking into on the car side of things? Anything I can test or examine that might cause this issue? I never experienced this with the old throttle body, that thing's problems were all on the PPS...doesn't mean something new hasn't come up on the car side of things, just that it never happened before.

On the off chance that ASI can't (or won't) be of help here, can anyone recommend a decent replacement TPS? I believe the OEM Denso product is out of production now?

Thanks!

 

This from another thread in our forum:
" with the car off, simply step on the accelerator pedal multiple times, in effect,
operating the potentiometers in the tps throughout their full range. Most potentiometers
have as part of their variable resister set up a "wiper" type device to clear the contact
surface, so operating the pot throughout its entire range can clear corrosion or debris
that is interfering with contact of the variable resister."

 

Digging in a bit more and finding a listing of OBD codes, I see that P1122 may after all be the PPS, the code list says that the pin 4 may be problematic, so I will investigate that connector when I get home tonight and see. The TSB 303-58 doesn't seem to mention, but I wonder if this pigtail is subject to the same issues as the TPS pigtail with dissimilar metal issues? If so, where does one go for a replacement end if its needed?

 

Randy, thanks for the info. I've give it a shot tonight as I'll be doing the PPS connector cleaning as well.

 

Disconnected the battery last night and left the negative cable end laying on top of the positive, disconnected the PPS connector and examined it. I completely forgot that the retaining clip broke off when I replaced the throttle body, but I had it ziptied on and the seemed pretty secure to me. None of the pins look questionable to me, all are gold colored, I see no abrasions on the wires so I think at least this connector is ok, minus the securing clip. I sprayed it and the PPS with contact cleaner and let them dry and worked a pick around inside each of the 4 connectors to scrape any contaminants off that I might reach, sprayed it again and reconnected it all. Left the battery disconnected overnight and later this evening I'll reconnect and try to recalibrate the throttle body and see how it goes.

Anyone know where I can locate a replacement connector? Photo attached.

In the meantime I have two emails and one phone message in to ASI without any replies from them in a couple days. Their phone system specifically states that all tech support must go through the website chat applet, however I could not find a chat link anywhere on any page, so I left a message with their customer service dept. Maybe I'll try calling sales instead, I bet they answer that line pretty promptly.

 

I had a similar problem with the PPS connector on my first 2000 VDP. I ended up cutting it off and soldering another one in its place which cured the trouble. In the meantime, I had gotten the TB serviced, installed a used TB, and replaced the TPS connector among other attempts. This went on over the course of a couple of years as it would work OK for a while then act up. It finally dawned on me it was the pedal position connector.

 

Recleaned and reconnected everything, nice shiny new zip tie on the PPS connector. Per ASI's instructions I connected the battery, powered the car on but didn't start it for 60 seconds to allow calibration to take place, then when I started it I got a rough idle initially, OBD reader showed me misfires in 3, 7 & 8, but it all smoothed out after about 30 seconds or so, no more misfires since then, these were accompanied by a code P1316, which also disappeared after driving. Unsure of what might have caused these to happen, but they all vanished on their own so I'm sure they'll never bother me again, right? RIGHT??

Couple days, about 200 miles so far and no hiccups. Still no word from ASI.

MIL came on when I initially started it, checked it after driving it those couple hundred miles, its showing a code P1647, which I believe indicates the upstream O2 sensor on the left side needs to be replaced. Bummer because they're spendy.

 

I am a firm believer that these cars were never meant to sit for long periods.
That is basically true for any and all cars but especially so Jaguars with all
the British designed electronic connections and the level of interdependency
that is evident.

 

Got the P1122 again on the way into work this morning. Happened twice today before I got to the parking lot. Contacted ASI again, hoping for a response. I'm frustrated with their lack of reply, but hoping they'll call me with a solution. If not I'll call their sales line, which I bet they answer.