P0121 TPS issues RESOLVED
#21
#22
I mean soldering new wires to the pins on the TPS, and installing a new plug further down the wiring, could be a cheap or free fix. Most of us have a soldering iron, spare wire, and somewhere we can salvage a cheap connector.
I would never expect any new part to be free, especially if it's gold plated, but $50 each for wires is ridiculous, even for Jaguar
I would never expect any new part to be free, especially if it's gold plated, but $50 each for wires is ridiculous, even for Jaguar
#23
A cheap connector (or at least the wrong selection of material) is what causes this problem in the first place. Very low currents of analog signals should have gold on gold contacts or else the contact resistance will increase and signal quality will degrade over time.
The gold plating thickness is also important to allow for serviceability over multiple mating cycles and to deal with the vibration wear in a vehicle.
If you use the wrong connector, the problem will likely just recur in the new connector eventually.
Also, soldering the TPS would need to be undertaken with great caution since it is unknown if the plastic housing is rated for soldering temperatures.
The gold plating thickness is also important to allow for serviceability over multiple mating cycles and to deal with the vibration wear in a vehicle.
If you use the wrong connector, the problem will likely just recur in the new connector eventually.
Also, soldering the TPS would need to be undertaken with great caution since it is unknown if the plastic housing is rated for soldering temperatures.
#24
#25
Another drawback to bypassing the failing connector, and installing another is the destructive effect such action can have on later owners. Having owned British cars that had the wiring 'doctored' with, installing a complete new harness makes the wiring diagram accurate again and fault diagnosis far easier.
#26
Understand that you are not getting a new connector with leads you are getting new tips with leads that go into the old connector. See the attached TSB
Link http://www.jagrepair.com/images/TSB/XK8/303-58.pdf
Link http://www.jagrepair.com/images/TSB/XK8/303-58.pdf
#27
Thanks for all the feedback everyone
I understand that the 'repair kit' is just for replacement tips and leads for the male (harness side) plug.
Unfortunately, not only do I have what appears to be corroding contacts, but the retaining clip on the female (TPS) end of the plug has broken off, so there is nothing to securely hold the plug in place, other than wrapping cable ties around it.
Hardwiring new wires to the TPS and installing a *decent* plug further down the harness potentially fixes both of these issues.
Of course... there is still the possibility that there is wear or damage on one of the tracks INSIDE the TPS itself.
I am trying to get hold of ASI to see whether their throttle body rebuild will solve all of these issues in one go, or if I will still be left with either a broken plug, or mismatched pins in the connector.
I understand that the 'repair kit' is just for replacement tips and leads for the male (harness side) plug.
Unfortunately, not only do I have what appears to be corroding contacts, but the retaining clip on the female (TPS) end of the plug has broken off, so there is nothing to securely hold the plug in place, other than wrapping cable ties around it.
Hardwiring new wires to the TPS and installing a *decent* plug further down the harness potentially fixes both of these issues.
Of course... there is still the possibility that there is wear or damage on one of the tracks INSIDE the TPS itself.
I am trying to get hold of ASI to see whether their throttle body rebuild will solve all of these issues in one go, or if I will still be left with either a broken plug, or mismatched pins in the connector.
#28
To resurrect this thread, I got all four contacts from SNG Barratt (who now have a nice picture of the part on their site thanks to my orders) and got around to doing this TSB. The plastic connector is pretty brittle and in the process of pulling out the old pins, my connector isn't in the best of shape anymore. From my understanding, it is difficult/near impossible to source a new plastic connector so, short of finding one from a breaker, I'm a little stuck. It does seem to be in good enough shape to hold everything in place and a few initial drives had me thinking I had this problem licked....then *BAM* Failsafe Engine Mode with P0121 is back.
New/Used Throttle Body at this point?
New/Used Throttle Body at this point?
#29
#30
To resurrect this thread, I got all four contacts from SNG Barratt (who now have a nice picture of the part on their site thanks to my orders) and got around to doing this TSB. The plastic connector is pretty brittle and in the process of pulling out the old pins, my connector isn't in the best of shape anymore. From my understanding, it is difficult/near impossible to source a new plastic connector so, short of finding one from a breaker, I'm a little stuck. It does seem to be in good enough shape to hold everything in place and a few initial drives had me thinking I had this problem licked....then *BAM* Failsafe Engine Mode with P0121 is back.
New/Used Throttle Body at this point?
New/Used Throttle Body at this point?
I chased a similar problem for quite a while- turned out to be the TPS/throttle body - these Denso TPS units all seem to fail eventually.
#31
I had this code and cleaned tb connectors but it came back. Intermittant. (99xk8) I topped up battery as well but code came back. I read somewhere about the ground connection under the computer module passenger side engine compartment. ( US car ) I disconnected computer ( cleaned those contacts as well ) and low and behold the ground connection to the body of the car was indeed loose. I could turn it by hand. I cleaned and torqued down. The code has never came back. Over 3 years now I think.
#32
#33
I didn't see any ground under the computer module, but I did clean the computer contacts as well as clean and add dielectric grease to every ground I could find. Plus I pulled the contacts from the battery, cleaned everything (despite looking perfect) regreased, and reconnected. So far, so good, but too soon to tell.
#34
Keith: I am sure there is a ground connector under there somewhere. Right to the body of the car. I was a little skeptical as the code was directing me to the tb. But with these cars if someone suggested to perform a voodoo pin thing with a model of the car I probably would !!! Mine is pretty much stored for the winter but if I get a chance will double check the placement of that ground as it has been a few years. Good luck and hope its gone for good.
#35
pigtail
Toyota TPS Sensor Repair Connector Throttle Position Connector Pigtail | eBayr
this looks like the one you need under $30 bucks new, pigtail connector, wiring, and all, don't fit, return it. Worth a try for under $30, but Im told by a Jaguar Salvage Dealer, it is the correct part for us.
2.Also, our TPS was branded a different "part number " for jags even though its used in other vehicles to rip us off is what he explained as well. Ill investigate that later.
this looks like the one you need under $30 bucks new, pigtail connector, wiring, and all, don't fit, return it. Worth a try for under $30, but Im told by a Jaguar Salvage Dealer, it is the correct part for us.
2.Also, our TPS was branded a different "part number " for jags even though its used in other vehicles to rip us off is what he explained as well. Ill investigate that later.
Last edited by aode06; 10-30-2014 at 09:22 AM.
#36
That is good information. Too bad I got the gold contacts already. I might buy that just for the plastic and stick the gold contacts into it. Do you just get one of the TPS that they have on eBay and put that on? I wonder why jaguar and others insist on an entire throttle body when so many other manufacturers just have you swap the TPS. I think the one for my old Cougar was about $15. So far I seem to have it licked, but I haven't put neigh miles on to tell for sure.
#37
Toyota TPS Sensor Repair Connector Throttle Position Connector Pigtail | eBayr
this looks like the one you need under $30 bucks new, pigtail connector, wiring, and all, don't fit, return it. Worth a try for under $30, but Im told by a Jaguar Salvage Dealer, it is the correct part for us.
2.Also, our TPS was branded a different "part number " for jags even though its used in other vehicles to rip us off is what he explained as well. Ill investigate that later.
this looks like the one you need under $30 bucks new, pigtail connector, wiring, and all, don't fit, return it. Worth a try for under $30, but Im told by a Jaguar Salvage Dealer, it is the correct part for us.
2.Also, our TPS was branded a different "part number " for jags even though its used in other vehicles to rip us off is what he explained as well. Ill investigate that later.
I'm trying to source a TPS at the moment for my spare throttle body - the only 198500-3250 I can find is via Aliexpress from China - $45 - but I'm reluctant to order from there in case it's a scam. If you point me in a direction I'll chase it up and see if it leads anywhere - it would be a great resource for all of us. P.M. me if you prefer.
#40
Hi all.
- TPS (actually throttleblade position) connector, PI 6, is a black 4-way Sumitomo TS090. May give P 0121.
- Pedal demand/mechanical guard connector, PI 42, is a black 5-way Yazaki 0902. May give P 1121.
- Both these feed to PI 1, a large 57-way connector in a bracket on top of front part of transmission. You can see it down aft of the throttle body. I would be very careful to disconnect, as you may bend the pins on reconnection. But you may try to waggle it.
- Throttle motor connector, PI 33, is a black 2-way twin clip. This is fed from a relay. Malfunction (poor connection) of this relay or its pins (legs), has been mistaken for TB failure.
- There are some differences between AJ26 TB and AJ27 (from VIN 0313039).
- Finally, here is link to another thread about TPS:
https://www.jaguarforums.com/forum/x...?highlight=tps
- TPS (actually throttleblade position) connector, PI 6, is a black 4-way Sumitomo TS090. May give P 0121.
- Pedal demand/mechanical guard connector, PI 42, is a black 5-way Yazaki 0902. May give P 1121.
- Both these feed to PI 1, a large 57-way connector in a bracket on top of front part of transmission. You can see it down aft of the throttle body. I would be very careful to disconnect, as you may bend the pins on reconnection. But you may try to waggle it.
- Throttle motor connector, PI 33, is a black 2-way twin clip. This is fed from a relay. Malfunction (poor connection) of this relay or its pins (legs), has been mistaken for TB failure.
- There are some differences between AJ26 TB and AJ27 (from VIN 0313039).
- Finally, here is link to another thread about TPS:
https://www.jaguarforums.com/forum/x...?highlight=tps
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