Front Pump Output Test
The special tests are designed to aid the technician in diagnosing the hydraulic and mechanical portions of the transmission. The front pump output test can also be used to detect a stuck or inoperative main control torque converter regulator valve. The datalogger is used to measure the amount of time it takes the vehicle to reach approximately 5 Km/h (3 MPH) at engine idle speed without pressing the accelerator pedal, verifying transmission pump operation.
- 2.
Park the vehicle for a minimum of 6 hours or overnight on a level spot where it can be driven forward uninhibited for up to 5 Km/h (3 MPH).
- 3.
Using a diagnostic scan tool, with Ignition On and Engine Off, select the following PIDs:- VSS Vehicle speed
- TRS Transmission Range selector
- BOO1 Brake On
- APP% Accelerator Pedal Position
- Gear_Mode Transmission gear
- TFT Transmission Fluid Temperature
- TSS_SRC Turbine Speed Sensor
- RPM Engine Revolutions
- Gear_Rat Transmission Gear ratio
- 4.NOTE: Read and review the following steps before performing them as they need to happen consecutively.
Make sure the parking brake is released prior to the next step.
- 5.NOTE: Do not apply the accelerator pedal for this test.
Press the record function and perform the following steps.
- Press the brake pedal.
- Start the engine.
- Immediately place the transmission selector lever in the D position.
- Immediately release the brake pedal and allow the vehicle to move at idle speed only. Do not accelerate.
- 7.
Using the scroll feature, slide the time bar to the point when the brake was released as indicated by PID BOO1, and note the time at the bottom.
- 9.
Did the vehicle reach 5 Km/h (3 MPH) within 5 seconds?- Yes - vehicle is operating normally. This procedure does not apply.
- No - replace the transmission pump assembly. Refer to: Transmission - 2.7L EcoBoost (238kW/324PS) . Refer to: Transmission .