P1810

P1810 WITH 4 SPEED AUTOMATIC

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Automatic Transmission Fluid Pressure Manual Valve Position Switch (TFP Val. Position Sw.) 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 Val. Position Sw. also contains the Automatic Transmission Fluid Temperature (TFT) sensor. These components are combined into one unit, mounted on the valve body. The Powertrain Control Module (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 illegal gear will be indicated (Refer to the illustrated TFP Val. Position Sw. 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 A DTC.

CONDITIONS FOR SETTING THE DTC

DTC P1810 sets when any one of the following three conditions occur:

Condition 1

^ The engine is running.

^ The gear range is illegal for 5 seconds (Refer to the TFP Val. Position Sw. Logic table).

Condition 2

^ The engine speed is in transition from 0 RPM to greater than 500 RPM.

^ The system voltage is 10-16 volts.

^ No Vehicle Speed Sensor (VSS) DTC P0502.

^ The vehicle speed is less than 11 km/h (7 mph).

^ D2, D4, or Reverse gear is indicated after start-up for 2 seconds.

Condition 3

^ The engine is running.

^ No Throttle Position (TP) Sensor DTCs P0121 P0122, or P0123

^ N6 VSS DTC P0502

^ No Input Speed Sensor DTCs P0716 or P0717

^ No illegal gear ranges detected (Refer to the TFP Val. Position Sw. Logic table).

^ The vehicle speed is at least 16 km/h (10 mph).

^ The TP is at least 15%.

And any one of the following three conditions occurs:

^ The TFP Val. Position Sw. indicates Park/Neutral when the gear ratio is less than 1:0.72 (4th gear) for 10 seconds.

^ The TFP Val. Position Sw. indicates Reverse when the gear ratio is greater than 1:2.23, or less than 1:2.02, for 5 seconds.

^ The TFP Val. Position Sw. indicates D, 3, 2, or 1 when the gear ratio indicates Reverse for 10 seconds.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM illuminates the Malfunction Indicator Lamp (MIL).

^ The PCM freezes shift adapts from being updated.

^ The PCM inhibits TCC engagement.

^ The PCM assumes a D4 shift pattern.

^ The PCM elevates line pressure.

^ DTC P1810 is stored in the PCM history.

CONDITIONS FOR CLEARING THE MIL/DTC

^ The PCM turns OFF the MIL after three consecutive ignition cycles 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

^ A pressure regulator problem could set DTC P1810.

^ Inspect the wiring for poor electrical connections at the PCM. Inspect the wiring for poor electrical connections at the transmission 20-way connector. Look 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

When diagnosing for an intermittent short or open condition, massage the wiring harness while watching the test equipment for a change.

TEST DESCRIPTION

The numbers below refer to the Step numbers on the diagnostic table.

4. This Step tests the PCM's ability to recognize an open circuit on signal A, B, and C ranges.

11. This Step verifies signal A circuit from the PCM.

12. This Step verifies signal B circuit from the PCM.

13. This Step verifies signal C circuit from the PCM.