Line Pressure Test

Line Pressure Test

This test verifies that the line pressure is within specifications.

CAUTION: The transmission tester MUST BE REMOVED and the vehicle harness installed when verifying these pressures.

CAUTION: Perform line pressure test prior to performing stall speed test. If line pressure is low at stall, do not perform Stall Speed Test or further transaxle damage will occur. DO NOT MAINTAIN WIDE OPEN THROTTLE in any gear range FOR MORE THAN FIVE SECONDS.

Pressure Tap Location:

1. Connect 0-2070 kPa (0-300 psi) pressure gauge to the line pressure tap.

Line Pressure Specifications:

2. Start engine and check line pressures. Refer to the chart shown to determine if line pressure is within specifications.

3. If line pressure is not within specifications,
perform On-Board Diagnostics,
Pinpoint Test E.
Perform Air Pressure Test and service the main control or pump assembly as required.
4. If line pressure is not within specification after mechanical checks and there are no DTCs, the electronic pressure control (EPC) solenoid may be mechanically malfunctioning.
5. Connect a pressure gauge to the EPC pressure tap.
- Start the engine and check EPC pressure. Refer to the Line Pressure Specification Chart previously shown for specifications.
- If the EPC is not correct, replace the EPC solenoid.
- If the EPC pressure is OK, refer to the Line Pressure Diagnosis Chart below for symptom definition.

LINE PRESSURE DIAGNOSIS CHART
Test Results Possible Source
HIGH at IDLE - ALL RANGES
- Wiring Harnesses
- EPC Solenoid
- Main Regulator Valve
LOW at IDLE - ALL RANGES
- Low Fluid Level
- Fluid Inlet Filter/Seal
- Main Control Body
- Cross Leaks
- Gaskets
- Pump
- Separator Plate
LOW in Park ONLY
- Valve Body
LOW in Reverse ONLY
- Separator Plate
- Reverse Clutch
- Valve Body
- Forward Clutch
LOW in Neutral ONLY
- Valve Body
LOW in Overdrive ONLY
- Forward Clutch
- Valve Body
LOW in Drive ONLY
- Forward Clutch
LOW in Manual First ONLY
- Forward Clutch
- Valve Body