I'm having these codes associated wth an engine fault light. The auto parts guy wasn't much help beyond giving me the codes. Can anyone give me some thoughts for this 1997 XK8? I suspect that it has been sitting for a while. Thanks

 

The good news is that the P1111 code says that everything in life is wonderful!

The bad news is that the P1227 code is not in the Jaguar list of manufacturer specific codes and is probably incorrectly read or just an error.

 

P1227 Mechanical Guard Sensor Circuit Low Voltage.

Mechanical guard sensor to ECM sense circuit low voltage,
ECM: open circuit or high resistance
Sensor power supply fault or Mechanical guard sensor failure.

Inhibits cruise control

The Mechanical Guard is near the Pedal Position Sensor on the Throttle Body.

 

Now I remember . . . the guard circuit is one of those things not well documented in any of the Jaguar literature.

 

Good save..

 

There are a number of differences between the Throttle Body on the AJ26 and the AJ27 Engines.

Mechanically, there are major differences between the default spring-loaded positions of the Throttle Plate and the intermediate linkage between the Pedal Position linkage and the Throttle Plate.

In the AJ26, a Mechanical Guard is Positioned between the Pedal Position Linkage and the Throttle Plate Linkage. The Cruise Control Vacuum Servo is connected to the Mechanical Guard Linkage.

The AJ27 Throttle Body uses the ECM to operate the Throttle Motor for Cruise Control and has no Mechanical Guard.

Both The AJ26 and AJ27 Throttle Bodies Have provision for a direct Mechanical connection from the Pedal to the Throttle Plate if the Throttle Motor Fails, but the mechanics are very different.