Hello all,
New player in the land of Jag though i am very e perienced with mechanical and electromechanical devices. I'm sure I'm not the only person who has run into not finding diagnostic information for the fly by wire throttle control located just in front of the bulkhead by the master cylinder on a LHD car. I can't seem to find diagnostics, pinouts, or replacement parts for this unit that has 6 wires to it and the throttle cable operates the sensor. It is separate from the throttle body. Is this a Ford part by chance? Seems this was a transition year for Jag. Any help is appreciated!

 

What year is your car and is it an XK8 or XKR? Do you have any other codes?

Bear in mind the throttle is the butterly in the throttle body. The Throttle Position Sensor reports the position of that butterfly. The Pedal Position Sensor is the sensor that is connected to the gas pedal via a cable. Make sure you understand which sensor you are fault finding.

I would start by cleaning the connectors, then checking the wiring from the harness back to the ECU.

 

Thank you for the reply! My apologies, this is an 03 XK8 convertible with the 4.2. It has the pedal sensor that is seperate from the TPS. I have tested the throttle motor with a 9 volt battery and it operates correctly. The TPS checks out with both the OBD reader live data and with the multimeter. Pinout tests between the ECU and TPS check out per the workshop manual, however, there is no reference to the APP sensor (accelerator pedal position).The only DTC is P0222, Throttle/Pedal Position Sensor/Switch 'B' Circuit Low. I have performed voltage and resistance tests between the ECU and TPS and relay, all checked good.
Thank you for any ideas!

 

Here is the DTC for your car:-



It is the Throttle Position Sensor Circuit 2 - it gives you the pin number on the ECM connector to check for shorts etc - if this checks out ok, then the TPS itself is the suspect. This is nothing to do with the accelerator pedal or APP sensor, so make sure you know which sensor you are looking at.

BTW just so you know, all X100s have fly by wire throttle control - i.e. the gas pedal controls a potentiometer connected to the ECM, and the ECM commands the throttle butterfly to move. The Throttle Position Sensor is the feedback from the butterfly position. Earlier cars also had a mechanical connection for limp home and safety limits, but the basic principle was the same - it's all electronic.

 

The part you refer to is the Pedal Position Sensor:- six connections. The TPS only has four, and is what the P0222 refers to. Here is a snip from the EG:



The only additional info the Electrical Guide gives is:
EM80-75 THROTTLE POSITION SENSOR 1 SIGNAL: IDLE = 0.60 V; FULL THROTTLE = 4.30 V
EM80-76 THROTTLE POSITION SENSOR 2 SIGNAL: IDLE = 1.48 V; FULL THROTTLE = 4.40 V
Note the voltage differential between the two.

So you can use a multimeter to check the above voltages at idle and WOT. However, this simple check won't necessarily pick up an intermittent TPS issue.

This thread of Shoreguy's may give you some more insight:
https://www.jaguarforums.com/forum/x...9/#post2871807

 

Thank you Michael, this is the info I was looking for. I'll update with progress report. Thanks all for the input!