Range Selector Displays Incorrect Range

Range Selector Displays Incorrect Range





Circuit Description

The transmission internal mode switch (IMS) is a sliding contact switch attached to the lower control valve body, within the transmission. The manual valve link assembly then connects the IMS to the manual valve. The 4 inputs to the transmission control module (TCM) from the IMS indicate which position is selected by the transmission selector lever. This information is used for computers and control systems as well as determining the transmission shift patterns. The input voltage level at the TCM is high, ignition voltage, when the IMS is open and low when the switch is closed to ground. The state of each input is available for display on the scan tool. The four input parameters represented are Signal A, Signal B, Signal C and Signal P, Parity.

Diagnostic Aids

Refer to Transmission Internal Mode Switch Logic.

Test Description

The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the IMS for an open ground circuit.
5. This step tests for correct reference voltage from the TCM.

Step 1 - Step 9:

Step 10 - Step 17: