P1819

DTC P1819





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 PCM indicate the position of the transmission range selector. The input voltage level at the PCM 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 PCM detects a combination of IMS signals that are not PARK or NEUTRAL while attempting to start the vehicle, then DTC P1819 sets. DTC P1819 is a type C DTC.

DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1819 Internal Mode Switch - No Start/Wrong Range

Conditions for Running the DTC
^ The ignition switch is in the CRANK position.
^ The engine speed is 10 RPM or less.

Conditions for Setting the DTC
The PCM detects a combination of IMS signals that do not indicate PARK or NEUTRAL for 0.5 seconds.

Action Taken When the DTC Sets
^ The PCM does not illuminate the malfunction indicator lamp (MIL).
^ The PCM inhibits TAP shift operation, if equipped.
^ The PCM records the operating conditions when the Conditions for Setting the DTC are met. The PCM stores this information as Failure Records.
^ The PCM stores DTC P1819 in PCM history.

Conditions for Clearing the DTC
^ A scan tool can clear the DTC.
^ The PCM clears the DTC from PCM history if the vehicle completes 40 warm-up cycles without a non-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.

Test Description

Step 1 - Step 6:

Step 7 - Step 14:

Step 15 - Step 20:

The numbers below refer to the step numbers on the diagnostic table.
3. HI values for all signals in both PARK and DRIVE 4 indicates the ground circuit is OPEN.
5. With the 20-way connector disconnected, all signals should indicate HI.
7. If one circuit affects the other, this indicates a short between the two circuits.
13. This step tests the internal transmission harness. If no fault is found in the harness, the fault will be in the switch.