P1816
DTC P1816 (3.5L)
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 three range signals from the PCM will be removed, and an invalid gear range will be indicated. Refer to Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic.
When the PCM detects P/N indicated with a drive gear ratio, DTC P1816 sets. DTC P1816 is a type B DTC.
DTC Descriptor
This diagnostic procedure supports the following DTC:
DTC P1816 Transmission Fluid Pressure (TFP) Valve Position Switch Indicates Park/Neutral (P/N) with Drive Ratio
Conditions for Running the DTC
^ No MAF DTCs P0101, P0102 or P0103.
^ No MAP DTCs P0107 or P0108.
^ No PSA DTCs P1810 or P1818.
^ The engine is running for 5 seconds and not in fuel cut off.
^ The vehicle speed is 5 km/h (3 mph) or more.
^ The TP indicated angle is 10 percent or greater.
^ The engine torque is greater than 34 Nm (25 ft. lbs.).
Conditions for Setting the DTC
The PCM detects P/N with a drive 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 commands an alternate coast shift pattern where downshifts occur at higher vehicle speeds while coasting.
^ The PCM freezes transmission adaptive functions.
^ The PCM disables TAP shift functions, if equipped.
^ 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 P1816 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 integrity of the engine harness and the PCM by checking 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 PCM.
