P1822
DTC P1822
Circuit Description
The transmission internal mode switch (IMS) is a sliding contact switch attached to the selector detent inside the transmission side cover. The 4 inputs to the transmission control module (TCM) indicate the position of the transmission range selector. The input voltage level at the TCM is high, B+, when the IMS is open and low when the switch is closed to ground. The 4 input parameters represented are Signals A, B, C, and P - Parity. Refer to Transmission Internal Mode Switch Logic.
If the TCM detects that IMS Signal B is always high, then DTC P1822 sets. DTC P1822 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1822 Internal Mode Switch B Circuit High Voltage
Conditions for Running the DTC
^ The engine speed is greater than 500 RPM for 5 seconds.
^ No engine torque malfunction.
^ The engine torque is 50 N.m (37 lb ft) or greater.
Conditions for Setting the DTC
The IMS Signal B is continuously high this ignition cycle, and the following conditions occur:
1. The IMS indicates PARK or NEUTRAL for 1 second or greater.
2. The IMS indicates transitional position D2-D1 for 8 seconds or greater.
Action Taken When the DTC Sets
^ The TCM requests the engine control module (ECM) to illuminate the malfunction indicator lamp (MIL) during the consecutive trip in which the Conditions for Setting the DTC are met.
^ The TCM commands maximum line pressure.
^ The TCM commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
^ The TCM freezes transmission adaptive functions.
^ The TCM disables the touch activated power (TAP) shift operation.
^ The TCM assumes D4 for shifting.
^ The TCM records the operating conditions when the Conditions for Setting the DTC are met. The TCM stores this information as Failure Records.
^ The TCM stores DTC P1822 in TCM history during the consecutive trip in which the Conditions for Setting the DTC are met.
Conditions for Clearing the DTC
^ A scan tool can clear the DTC.
^ The TCM clears the DTC from TCM history if the vehicle completes 40 warm-up cycles without an emission-related diagnostic fault occurring.
^ The TCM cancels the DTC default actions when the ignition switch is OFF long enough in order to power down the TCM.
Test Description
The number below refers to the step number on the diagnostic table.
3. This step tests the integrity of the engine harness and TCM by inspecting for the Signal B state change from HI to LOW. A LOW signal indicates the fault is either in the internal transmission harness or the switch. A HI signal indicates the fault is either in the engine harness or the TCM.
