P1825

DTC P1825

Steps 1-4:

Steps 5-11:

Steps 12-19:

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 four inputs to the PCM from the IMS indicate which position is selected by the transmission selector lever. This information is used for engine controls as well as determining the transmission shift patterns. The input voltage level at the PCM 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.
If the PCM detects a combination of IMS inputs that are invalid, then DTC P1825 sets. DTC P1825 is a type B DTC.

Conditions for Running the DTC
The engine run time is greater than 5 seconds.

Conditions for Setting the DTC
The PCM detects an invalid IMS range for 5 seconds.

Action Taken When the DTC Sets
^ The PCM illuminates the malfunction indicator lamp (MIL) during the second consecutive trip in which the Conditions for Setting the DTC are met.
^ The PCM commands maximum line pressure.
^ The PCM assumes a D4 shift pattern
^ The PCM freezes transmission adaptive functions
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Freeze Frame and Failure Records.
^ The PCM stores DTC P1825 in PCM history during the second consecutive trip in which the Conditions for Setting the DTC are met.

Conditions for Clearing the MIL/DTC
^ The PCM turns OFF the MIL during the third consecutive trip in which the diagnostic test runs and passes.
^ A scan tool can clear the MIL/DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The PCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the PCM.

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 INS for an open ground circuit.
5. This step tests for correct reference voltage from the PCM.