P1811

P1811 WITH 4 SPEED AUTOMATIC

Diagnostic Chart:

Wiring Diagram:

CIRCUIT DESCRIPTION

The Powertrain Control Module (PCM) modifies the transmission line pressure through the Pressure Control Solenoid Valve (PC Sol. Valve), in order to control shift execution time and shift consistency. The PCM monitors various inputs, and modifies the shift execution and timing by applying a calculated duty cycle to the PC Sol. Valve. The PCM alters the shifting based on driving habits, transmission load, and internal transmission condition.

When the PCM detects long shifts that can not be shortened by shift adapts during the same ignition cycle, then DTC P1811 sets. DTC P1811 is a type D DTC.

CONDITIONS FOR SETTING THE DTC

The shift time is greater than 1.8 seconds at maximum adapt, for a total of five times during the same ignition cycle.

ACTION TAKEN WHEN THE DTC SETS

^ The PCM does not illuminate the Malfunction Indicator Lamp (MIL).

^ The PCM commands maximum line pressure.

^ The PCM freezes shift adapts from being updated.

^ DTC P1811 is stored in the PCM history.

CONDITIONS FOR CLEARING THE DTC

^ 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

^ Ask the customer about overloading the vehicle, exceeding the trailer-towing limit, or towing in Overdrive.

^ If, after several unsuccessful attempts to gain accurate shift times, and an adapt can be made, reset adapts and operate the vehicle, in order to assure proper shifting.

TEST DESCRIPTION

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

2. This Step tests for low fluid level, which can cause delayed shifts.

4. This Step tests for low line pressure, which can cause delayed shifts.

12. When DTC P1811 sets, the PCM commands maximum line pressure and does not inhibit TCC engagement. This can lead to excessive heat build-up, causing the Torque Converter to balloon. You must replace the Torque Converter.