It was all going so well.........perhaps too well! I stopped at a friends house the other day and when I got back in and started up again I had the Fail Safe Mode, T.C. not available and ASC not available. No throttle response, fast rough idle, red, amber and engine lights on.
I had it recovered back to my place and put my Autel reader on it and there was the P1121 and P1122 codes. I have cleared the codes, charged the battery and carried out a hard re set, all to no avail. It simply throws the same codes again as soon as I power up the ignition.
So, from going through JTIS, my understanding is that this is the Pedal Position Sensor and there is a mismatch between the two circuits within it.
I am going to carry out the harness testing as per JTIS, but my guess is that the sensor has failed and needs replacing. I'm aware that this should involve replacing the whole throttle body but I have two questions. First, why is it not possible to replace only the faulty sensor and secondly, does anyone know of a reliable company in the UK to rebuild the throttle body?
Thanks all,

Andy.

 

It's not possible to just replace the TPS because Denso ,under the terms of their supply agreement, are not allowed to supply the aftermarket. I, and a few others, have tried to source equivalents from the far east, all to no avail. The 198500-3250 TPS is fitted to other cars, rumoured to be Toyota/Lexus/Isuzu/Mazda but not under the same P.N..The two outputs on the TPS are offset, hence the difficulty in finding something that will fit. I had my TB rebuilt last year and the TPS was rebuilt rather than renewed. If you do a search on here and find a thread started by a former member Steve in France that will tell you masses about the TPS..As far a rebuilders in the UK are concerned I'm sure someone will chime in. Just check all the wiring to the TPS before committing to a rebuild - there was a TSB for incompatible connectors at one point plus a loose/poor connection could give the same faults - unlikely but possible.

 

Try pulling the harness at the throttle body and cleaning with contact cleaner. Clean the plug contacts and then re-install. With a little luck your problem should be gone. Happens to me with severe temperature change or heavy fog like moisture.

 

I have 3 4.0L V8 Jags, and in one of my cupboards, in a box, is THE most essential spare part for a Jag - a throttle body! Put a search on Ebay and buy the best one under £100. You won't regret it (call it insurance).

Make sure it's the right one - the early ones have vacuum operation, the later are all electric.