P1810
Diagnostic Chart:
Diagnostic Chart:
Description:
Wiring Diagram:
CIRCUIT DESCRIPTION
The Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) consists of five pressure switches (two normally-closed and three normally-open) and a Transmission Fluid Temperature (TFT) sensor combined into one unit. The combined unit mounts on the valve body.
The Powertrain Control Module (PCM) supplies the battery voltage for each range signal. By grounding one or more of the circuits through various combinations of the pressure switches, the PCM detects which manual valve position you select. The PCM compares the actual voltage combination of the switches to a Transmission Fluid Pressure (TFP) Val. Position Sw. combination table stored in memory.
The TFP Val. Position Sw. cannot distinguish between Park and Neutral because the monitored valve body pressures are identical. With the engine OFF and the ignition switch in the RUN position, the TFP Val. Position Sw. indicates Park/Neutral. Disconnecting the transmission 20-way connector removes the ground potential for the three range signals to the PCM. In this case, with the engine OFF, and the ignition switch in the RUN position, D2 will be indicated.
When the PCM detects an invalid state of the TFP Val. Position Sw. or the TFP Val. Position Sw. circuit by deciphering the TFP Val. Position Sw. inputs, then DTC P1810 sets. DTC P1810 is a type B DTC.
CONDITIONS FOR SETTING THE DTC
DTC P1810 sets if any of the following Conditions occurs two consecutive times:
^ Condition 1 detects an illegal switch combination.
^ Condition 2 detects D2, D4 or Rev during an engine start.
^ Condition 3 detects Park or Neutral when the vehicle should be in D4.
Condition 1
^ The system voltage is 8-16 volts.
^ The engine speed is greater than 450 RPM for 5 seconds.
^ Not in fuel cutoff.
^ The PCM detects an illegal Transmission Fluid Pressure (TFP) Val. Position Sw. state.
^ All conditions met for 60 seconds.
Condition 2
^ No Vehicle Speed Sensor (VSS) Assy. DTCs P0502 or P0503.
^ The system voltage is 8-16 volts.
^ The engine speed is less than 80 RPM for 0.1 second; then
the engine speed is 80-600 RPM for 0.8 second; then
the engine speed is greater than 600 RPM.
^ The vehicle speed is less than 3 km/h (2 mph).
^ The detected gear range is D2, D4 or Rev.
^ All conditions met for 5 seconds.
Condition 3
^ No VSS Assy. DTCs P0502 or P0503.
^ The selected gear range is D4.
^ The engine speed is greater than 450 RPM for 5 seconds.
^ Not in fuel cutoff.
^ The speed ratio is 0.65-0.75 (the speed ratio is the engine speed divided by the transmission output speed).
^ The system voltage is 8-16 volts.
^ The Throttle Position (TP) angle is 10-50%.
^ The engine torque is 40-450 lbs. ft.
^ The engine vacuum is 0-105 kPa.
^ The Torque Converter Clutch (TCC) is locked ON.
^ The detected gear range is Park/Neutral.
^ All conditions met for 10 seconds
ACTION TAKEN WHEN THE DTC SETS
^ The PCM illuminates the Malfunction Indicator Lamp (MIL).
^ The PCM commands D2 line pressure.
^ The PCM commands a D4 shift pattern.
^ The PCM freezes shift adapts from being updated.
^ DTC P1810 stores in PCM history.
CONDITIONS FOR CLEARING THE MIL/DTC
^ The PCM turns OFF the MIL after three consecutive trips without a failure reported.
^ A scan tool can clear the DTC from the PCM history. The PCM clears the DTC from the PCM history if the vehicle completes 40 warm.up cycles without a failure reported.
^ The PCM cancels the DTC default actions when the fault no longer exists and the ignition is OFF long enough in order to power down the PCM.
DIAGNOSTIC AIDS
^ Refer to the TFP Valve Position Switch Logic table for the normal range signals and the illegal combinations. On the table, ON is 0 volts, OFF is B+.
^ Inspect the wiring at the PCM, the transmission connector and all other circuit connecting points for the following conditions:
- A bent terminal.
- A backed out terminal.
- A damaged terminal.
- Poor terminal tension.
- A chafed wire.
- A broken wire inside the insulation.
- Moisture intrusion.
- Corrosion.
^ When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.
^ Refer to the TFP Valve Position Switch Resistance Check or the Functional Test Procedure for further information.
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 actually selected.
4. This step tests for correct voltage from the PCM to the transmission 20-way connection