Special Testing Procedures
Special Testing Procedures
The special tests are designed to aid the technician in diagnosing the hydraulic and mechanical portion of the transaxle.
Engine Idle Speed Check
Refer to the Computers and Control Systems Information for diagnosis and testing of the engine idle speed.
Line Pressure Test
NOTICE: Carry out the Line Pressure Test prior to carrying out the Stall Speed Test. If line pressure is low at stall, do not carry out the Stall Speed Test or further transaxle damage will occur. Do not maintain Wide Open Throttle (WOT) in any gear range for more than 5 seconds.
NOTE: Certain sensor failures may cause high pressure control, failure mode effect management actions. Make sure that self-test and electrical repairs have been carried out, or test results may be incorrect.
This test verifies that the line pressure is within specifications.
1. Remove the line pressure tap plug.
2. Install a 1/8 x 28-to-1/8 x 28 pipe thread adapter into the line pressure tap.
3. Connect the Hydraulic Pressure Gauge to the adapter.
4. Start engine and check line pressures. Refer to the following Line Pressure Chart to determine if line pressure is within specifications.
5. If line pressure is not within specification, refer to Line Pressure Diagnosis Chart for line pressure concern causes.
6. Once the Line Pressure Test is complete, install the line pressure tap plug.
- Tighten to 13 Nm (115 lb-in).
Line Pressure Chart
Line Pressure Diagnosis Chart
Stall Speed Test
WARNING: Block all wheels, set the parking brake and firmly apply the service brake to reduce the risk of vehicle movement during this procedure. Failure to follow these instructions may result in serious personal injury.
NOTICE: Always carry out the Line Pressure Test procedures prior to carrying out the Stall Speed Test. If line pressure is low at stall, do not carry out the Stall Speed Test or further transaxle damage will occur.
NOTE: The Stall Speed Test should be carried out with the engine and transaxle at normal operating temperatures.
This test checks operation of the following items:
- Torque Converter Clutch (TCC)
- Forward clutch
- Low One-Way Clutch (OWC) assembly
- Engine driveability concerns
1. Connect a scan tool.
2. NOTICE: After testing each of the following ranges D, 2, 1 and R, move the selector lever to N (NEUTRAL) and run the engine at 1,000 rpm for about 15 seconds to allow the torque converter to cool before testing the next range. Failure to allow the torque converter to cool can cause the transaxle to overheat.
NOTICE: Do not maintain Wide Open Throttle (WOT) in any range for more than 5 seconds or transaxle damage can occur.
NOTICE: If the engine rpm recorded by the tachometer exceeds maximum specified rpm, release the accelerator pedal immediately, or further transaxle damage will occur. Clutch or band slippage is indicated.
NOTE: Prolonged use may set DTCs P0712 and/or P1783. After carrying out Stall Speed Test, run On-Board Diagnostic (OBD) Test and clear DTCs from memory.
Press accelerator pedal to floor Wide Open Throttle (WOT) in each range. Record rpm reached in each range. Stall speeds should be as follows:
Stall Speed Chart
3. If stall speeds were too high, refer to the following Stall Speed Diagnosis Chart. If stall speeds were too low, first check the engine idle speed. If engine idle is OK, remove the torque converter and check the torque converter One-Way Clutch (OWC) for slippage.
Stall Speed Diagnosis Chart
Air Pressure Tests
Transaxle Air Pressure Test Plate
A no-drive condition can exist even with correct transmission fluid pressure because of inoperative clutches or bands. An erratic shift can be located through a series of checks by substituting air pressure for transmission fluid pressure to determine the location of the failure.
Follow the procedure to determine the location of the inoperative clutch or band by introducing air pressure into the various test plate passages.
NOTE: Use only dry, regulated 300 kPa (44 psi) maximum air pressure.
Apply air to the appropriate passage(s). A dull thud should be felt or heard or movement should be observed when the component applies. There should be no hissing sound when the component is fully applied.
1. Drain transmission fluid and remove the transmission fluid pan.
2. Remove the main control valve body. Refer to Main Control .
3. Install the Air Test Plate and Gasket. Use the transmission fluid pan bolts to hold the test plate down.
- Tighten the bolts to 10 Nm (89 lb-in).
4. Apply air to the appropriate clutch port (refer to the diagram). A dull thud may be heard or movement felt when the component is applied or released. If clutch seals or check balls are leaking, a hissing sound may be heard.
If test results indicate that the servos do not operate, disassemble, clean and inspect them to locate the source of the concern.
If air pressure applied to the clutch passages fails to operate a clutch, or operates another clutch simultaneously, disassemble and use air pressure to check the transmission fluid passages in the center support and clutches to detect obstructions.