P1810

Diagnostic Chart (Part 1 Of 3):

Diagnostic Chart (Part 2 Of 3):

Diagnostic Chart (Part 3 Of 3):

Schematic:

Circuit Description with 4T40-E / 4T45-E Automatic Transaxle
The automatic Transmission Fluid Pressure (TFP) manual valve position switch consists of six pressure switches. Five of the switches are normally-open, and determine gear range selection. The sixth 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, mounted on the valve body.

The PCM provides battery voltage on the three 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 will be indicated. Refer to the Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic table.

When the PCM detects any of the following conditions, DTC P1810 sets.
^ An invalid gear state
^ A drive range after start-up
^ An incorrect gear ratio

DTC P1810 is a type B DTC.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ The system voltage is 8-18 volts.

CONDITIONS FOR SETTING THE DTC
One of the following three cases occurs:

Case 1
The gear range is illegal for 60 seconds (Refer to the Transmission Fluid Pressure (TFP) Manual Valve Position Switch Logic table).

Case 2
^ No VSS DTCs P0502 or P0503.
^ The engine speed is in transition from 0 RPM to greater than 600 RPM.
^ The vehicle speed is less than 3 km/h (2 mph).
^ D2, D4 or Reverse gear is indicated after start-up for 2 seconds.

Case 3
^ No TP DTCs P0121, P0122, or P0123.
^ No VSS DTCs P0502 or P0503.
^ No AT ISS DTCs P0716 or P0717.
^ No shift solenoid DTCs P0751, P0753, P0756 or P0758.
^ The TP is greater than 10%.
^ The vehicle speed is greater than 8 km/h (5 mph).
^ Engine torque is greater than 14 N.m (10 lb ft).
^ All of the above conditions are met and one of the following occurs for 5 seconds:
- The TFP manual valve position switch indicates PARK/NEUTRAL when the gear ratio is less than 0.72:1 (4th gear).
- The TFP manual valve position switch indicates REVERSE when the gear ratio is greater than 2.23:1, or less than 2.02:1.
- The TFP manual valve position switch indicates D4, D3, D2 or D1 when the gear ratio indicates REVERSE.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL) during the second consecutive trip in which the Conditions for settings the DTC are met.
^ The PCM elevates line pressure.
^ The PCM assumes a D4 shift pattern.
^ The PCM freezes shift adapts from being updated.
^ 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 P1810 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 fault no longer exists and/or the ignition switch is OFF long enough in order to power down the PCM.

DIAGNOSTIC AIDS
^ A pressure regulator condition could set DTC P1810.
^ Ensure the transmission linkage from the select lever to the manual valve is adjusted properly.
^ Inspect the connections at the PCM, the TFP manual valve position switch and all other circuit connecting points for an intermittent condition. Refer to Testing for Intermittent and Poor Connections in Diagrams.
^ Inspect the circuit wiring for an intermittent condition. Refer to Testing for Electrical Intermittents in Diagrams.

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.
4. This step tests for correct voltage from the PCM.