[akorna]

Guys - Thanks for the reply. I typed faster than I was thinking. The voltage tests were done with the ignition on. ALLDATA for 99 Cherokee says range with throttle closed should be 0.26-0.95v. That compares with the "greater than 200 mv and 0.8v specs you passed on. My TPS meets the spec requirements - just puzzled why the scanner shows the throttle is 15% open. My other OBD II vehicles show 0%. Something is off.

	Throttle position sensor A throttle position sensor (TPS) is a sensor used to monitor the position of the throttle in an internal combustion engine. The sensor is usually located on the butterfly spindle so that it can directly monitor the position of the butterfly throttle valve. The sensor is usually a potentiometer and therefore provides a variable resistance dependent upon the position of the butterfly valve (and hence throttle position). The sensor signal is used by the Engine Control Unit (ECU) as an input to its control system. The ignition timing and fuel injection timing (and potentially other parameters) are altered depending upon the position of the throttle, and also depending on the rate of change of that position. For example, in fuel injected engines, in order to avoid stalling, extra fuel may be injected if the throttle is opened rapidly (mimicking the accelerator pump of carburetor systems).