P1818

DTC P1818 (3.4L)

Circuit Description
The automatic Transmission Fluid Pressure (TFP) manual valve position switch consists of three pressure switches. two of the switches are normally-open, and determine gear range selection. The third switch is normally-closed, and detects Torque Converter Clutch (TCC) release fluid pressure. The TFP manual valve position switch also contains the automatic Transmission Fluid Temperature (TFT)sensor. These components are combined into one unit, attached to the control valve body.

The Powertrain Control Module (PCM) provides battery voltage on the two range signal circuits. By grounding one or more of the switches with fluid pressure from the manual shift valve, the PCM detects the selected gear range. When you disconnect the transmission electrical connector and the ignition is ON, the ground potential for the range signals from the PCM will be removed, and an invalid gear range will be indicated.

When the PCM detects a drive gear with a REVERSE ratio, DTC P1818 sets. DTC P1818 is a type B DTC.

Conditions for Running the DTC
^ No MAF DTCs P0101,P0102 or P0103.
^ No MAP DTCs P0107 or P0108.
^ No PSA DTCs P1810 or P1316.
^ The engine is running for greater than 5 seconds.
^ The vehicle speed is 5 km/h (3 mph or greater.
^ The TPS is 10 percent or greater.
^ The engine torque is greater than 34 Nm (25 ft. lbs.).

Conditions for Setting the DTC
The PCM detects a drive range with a REVERSE ratio 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 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 P1818 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.

Test Description
The numbers below refer to the step numbers on the diagnostic table.
3. This step tests the indicated range signal to the manual valve range actually selected.
6. This step tests for correct voltage from the PCM.

Steps 1-5:

Steps 6-13:

Steps 14-17:

DTC P1818 (3.4L)