I have replaced the throttle body in my ‘02 XKR with a new one due codes 172 &175. Now, no codes but now idling high at 800/900 rpms. Do I need to flash the ecu? Really flummoxed on this one.

 

jtclark11, I would try cleaning it first. Specifically, get a can of carb cleaner (not recommended, but generally available in more places) or throttle body cleaner. Open up the intake, spray everything that is not silver. Use your finger to open up the throttle body and get a smuch brown gone as possible. The final step is to spray some cleaner on to a rag and then wipe the edge of the butterfly valve as the gum on this edge can cause the throttle body to hang open slightly, causing a higher than normal idle.

Now, odds are, your car is going to be flooded at this point from all the carb/throttle body cleaner and the car is not going to want to start. Not a problem. When you go to start the car, depress the gas pedal down as far as it will go. I know what you are thinking. This is going to cause the engine to rev to its limiter. Actually quite the opposite. This is a command to the ECU to not activate the fuel injectors and all it does is pass air through the engine. After a few seconds of cranking the engine, start easing off the gas pedal. The engine should catch and come up to idle.

If this does not restore normal idle, then I would recommend switching over to the XK section of the forums as they will have more detailed information than what I am providing.

 

This throttle body has been rebuilt and is spotless. Are you recommending to clean another part attached to the body?

 

jtclark11, Not being completely familiar with the XK, I am making some logical leaps here. Like other Jaguars, you should see a small hole on the upstream side of the butterfly valve. This is a bleed hole that goes to the idle control valve. Clean out that hole (assuming you have one). Sometimes you may have an externally mounted one. The diagrams that I have are for a 2003+ XK and I am not sure if your 2002 has the same wiring setup. I know there is a difference between say a 2001 XJ 4.2L wiring and the 2003 XK, yet both used the same engine. So, i know there were changes being made to various components in this time. But, the two cars shared a lot of things.

The other thing that it could possibly be is the person that rebuilt your throttle body did not properly mount the throttle body position sensor. If they turn it too far one way, the gas pedal feels a bit unresponsive. But, if you turn it too far the other way, the ECU sees the sensor as being "open slightly" and it commands the throttle body to open slightly. This is where you can try putting a mark between the sensor and the throttle body for where it is now (so you can put it back if this does not work) and what you can do is there should be 2 screws holding the sensor in place. Loosen them slightly so you can bump the sensor around its shaft. What you want to do is turn it so the idle drops and then bring it back to the point just before it starts to raise the idle. That should bring your idle back to normal.

If this does not help you out, then as I mentioned before, put in a message in the XK forum and I am sure someone there has run into this same issue and will give you some useful information.

 

Could be wrong TPS / badly adjusted.

If searching be sure to use the FULL code.

No.