The Closed Throttle Position switch (CTP) is located either in the TPS (3.0L and 3.5L engines) or in the Idle Speed Control Motor (ISCM) assembly (2.4L engines). The CTP sends electrical signals to the ECM, telling it whether the accelerator is depressed or released. The ECM regulates the idle-speed control motor based upon those signals. Voltage within the ECM is applied, by way of the resistance, to the CTP. When the foot is taken off of the accelerator, the CTP is switched on and the current is grounded. As a result, the CTP voltage changes from a high to a low level.
If there is an abnormal condition of the CTP output even though the results of the check of the CTP and harness, the cause may be either improper adjustment of the accelerator cable or the cruise control cable, or improper adjustment of the fixed Speed Adjusting Screw (SAS).
| Fig. 1: The location of the CTPS on the 3.0L and 3.5L
engines is inside the Idle Speed Control Motor (ISCM)
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