Transaxle Tester Testing Procedures
ELECTRICAL SYSTEM TEST [LA4A-EL]Transaxle Tester Instruction
The transaxle tester allows a technician to operate the electrical portion of the transaxle independent of the vehicle electronics to determine specific transaxle concerns. The transaxle tester usage is divided into five steps.
1. Preliminary testing and diagnosis.
2. Installing the transaxle tester.
3. Static testing-engine OFF.
4. Dynamic testing-engine running.
5. Removing the transaxle tester and clearing Diagnostic Trouble Codes (DTCs).
Preliminary testing and diagnosis
Before any diagnostic testing is done on a vehicle, some preliminary checks must be performed, as outlined below. Be sure to write down your findings, especially any DTC, for future reference.
1. Verify customer's concern
- upshift
- downshift
- coasting
- engagement
- noise/vibration
1. If noise/vibration, check for dependencies:
- engine speed dependent
- vehicle speed dependent
- shift dependent
- gear dependent
- range dependent
- temperature dependent
2. Vehicle at normal operating temperature.
3. Inspect fluid level and condition.
4. Visually inspect the vehicle for the following items:
- vehicle modifications
- electronic add-on items
- leaks
- proper linkage adjustments
5. Inspect Service Bulletins and on-line repair information.
6. Perform vehicle on-board diagnosis test.
Transaxle tester installation
Installing the transaxle tester at the solenoid body connector allows the separation of the vehicle electronics from the transaxle electronics. Disconnecting the normal vehicle electronics will set additional DTCs and cause firm shifts. (Disconnecting the transaxle connector defaults the transaxle to maximum line pressure).
Note During tester usage, additional DTCs may be set. Therefore, it is important that all DTCs are erased after repairs have been made. To verify elimination of all DTCs, rerun the On-Board Diagnostic Test.
Caution Do not attempt to pry off connectors with a screwdriver. This will damage the connector and could result in a transaxle concern.
1. Disconnect the emission harness at the transaxle connector and at the TSS connector on the oil pump body in the LH wheel arch.
2. Turn the tester solenoid select dial to the "OHMS CHECK" position.
Caution Route all cables away from heat sources.
3. Install the SST (Transaxle overlay) onto tester. Connect the SST (Transaxle diagnostic harness) to the transaxle tester and then to the appropriate solenoid body connector and turbine shaft speed (TSS) connector.
Caution Route all gauge lines away from heat sources.
Warning Removing the line pressure inspection port bolt when the ATF is hot can be dangerous. Hot ATF can come out of the opening and badly burn. Before removing the line pressure inspection port bolt, allow the ATF to cool.
4. Remove the line pressure inspection port plug then connect the SSTs.
5. Plug the transaxle tester power supply plug into the cigarette lighter socket. At this time, all LED's should illuminate for a short period and then turn off. This is the tester internal circuit inspection.
6. Set the Bench/Drive switch to "BENCH" mode.
Static Testing-Engine "OFF"
Static testing procedures allow for shop testing of the transaxle in the vehicle or on the bench. Completion of these tests the transaxle electronically.
Caution For resistance checks, be sure that the tester solenoid select dial is set to the "OHMS CHECK" position or the ohmmeter may be damaged.
Resistance/continuity tests
- Using a volt-ohmmeter and the transaxle tester, perform the Pinpoint Tests based on the DTC which were displayed.
- Perform repairs as indicated by the Pinpoint Tests. Always retest and road test the vehicle after a repair.
Resistance/continuity test-solenoids
Solenoids (Electronic Pressure Control (EPC), Shift solenoid No.1 (SS1), Shift solenoid No.2 (SS2), TCC, 3-2 Timing/coasting clutch solenoid (3-2T/CCS)
1. Set an ohmmeter to the 0 - 100 ohm range.
2. Connect the positive lead of the ohmmeter to the appropriate VPWR jack for the solenoid being tested.
3. Connect the negative lead of the ohmmeter to the appropriate solenoid (EPC, SST, SS2, TCC,3-2T/CCS) jack.
4. Record the resistance.
5. Refer to the chart for the values.
- If out of specified range, refer to the DTC troubleshooting.
Resistance/continuity test-transaxle fluid temperature (TFT) sensor
1. Set an ohmmeter to the 1,000 ohm range.
2. Connect the positive lead to the + TFT jack.
3. Connect the negative lead to the - TFT jack.
4. Record the resistance. Resistance will vary with temperature.
5. Refer to the chart for the valves.
- If out of specified range, refer to the DTC troubleshooting.
Resistance/continuity test-turbine shaft speed (TSS) sensor
1. Set an ohmmeter to the 1,000 ohm range.
2. Connect the positive lead to the +TSS jack.
3. Connect the negative lead to the -TSS jack.
4. Record the resistance.
5. TSS should be 140-290 ohm.
- If out of specified range, refer to the DTC troubleshooting.
Voltage test-solenoids
Note LED will turn "GREEN" when solenoid activates and turn "OFF" when deactivated. LED will turn "RED" if an activated solenoid/harness is shorted to BAT+. LED will remain "OFF" if an activated solenoid/harness is shorted to ground or no continuity.
1. Set Bench/Drive switch to "BENCH" mode.
2. Set an voltmeter to the 20 volt D.C. range.
3. Connect the voltmeter positive lead to the appropriate solenoid VPWR jack.
4. Connect voltmeter negative lead to the appropriate solenoid lack.
5. Using the voltmeter, inspect for voltage across each solenoid by activating the solenoid switch. Select the appropriate solenoid with the rotary switch and depress the corresponding solenoid switch. The "LED" should illuminate, the voltage should change, and an audible click is heard. If "LED" does not illuminate, there is a short to ground condition.
6. Observe and record the values.
Dynamic Testing-Engine running
Dynamic testing is the final step in the transaxle tester usage. It allows the transaxle to be proven out electronically and hydraulically.
Preliminary set up
1. Set the Bench/Drive switch to DRIVE mode.
2. Rotate the GEAR SELECT dial on tester to the "1" position.
3. Set parking brake and confirm vehicle is in PARK.
4. Start the engine.
Electrical pressure control (EPC) solenoid
Caution Do not attempt to keep the EPC switch depressed (minimum line pressure) and stall the transaxle (holding the vehicle with the brake while depressing the throttle with the transaxle in gear). Transaxle will be damaged.
1. Observe the line pressure. Record the value. Line pressure should raise to maximum. If not, see Transmission Control Systems or DTC troubleshooting concerning the EPC solenoid.
2. Depress the EPC switch. Line pressure should drop to a minimum value. Record the value. If not, see Transmission Control Systems or DTC troubleshooting.
Transaxle engagement
Note Engagement will be harsh and line pressure will be at maximum regardless of the EPC switch during reverse check.
1. Verily that the Bench/Drive switch is in "DRIVE" mode.
2. Turn GEAR SELECT dial from 1 to 3/R.
1. Move the selector lever from PARK to REVERSE.
- Did vehicle shift into REVERSE?
- Was engagement harsh?
2. Move the selector lever from REVERSE to PARK.
3. Turn GEAR SELECT dial to 1.
1. Depress EPC switch. Line pressure should drop to idle pressure.
2. While holding the EPC switch down, move the selector lever from PARK to DRIVE.
- Did the vehicle shift into DRIVE?
- Was engagement smooth?
3. Move the selector lever from DRIVE to PARK.
4. Release EPC switch. Pressure should return to maximum.
5. With the EPC switch released, repeat steps 3-2 and (3). Engagement should be firm.
Upshift downshift
Note
- GEAR SELECT dial must be in "3/R" to get REVERSE gear.
- Upshifts and downshifts will be FIRM during this procedure.
- Pressure gauges may be removed from the vehicle during these tests.
- These tests should be performed on the road. If they are performed on the hoist, the technician may not feel all of the shifts when they are engaged.
- LED's will turn "green" when solenoids are activated and turn "off" when deactivated. Refer to the appropriate overlay for the proper status/shift sequence of the shift solenoids during upshift and downshift.
Caution Selector lever must be in the D range position or internal damage could result. Do not shift to 2 or 1 range position.
1. Verify that the GEAR SELECT dial is in "1" position. Move the selector lever into the D range. Depress the 3-2 timing/coasting clutch solenoid (3-2 T/CCS) button and accelerate the vehicle. If there is no vehicle movement, inspect the forward one-way clutch. If movement occurs, proceed to step 2 and continue diagnosis.
2. Move the selector lever into D range and accelerate to 23 km/h (14 mph). Select second gear by rotating the GEAR SELECT dial to "2" position.
- Did the vehicle upshift to second gear?
- Did the appropriate shift solenoids activate/deactivate?
3. Accelerate to 40 km/h (25 mph) and select "3" position.
- Did the vehicle upshift to third gear?
- Did the appropriate shift solenoids activate/deactivate?
4. Accelerate to 56 - 72 km/h (35 - 45 mph) and select "4" position.
- Did the vehicle upshift to fourth gear?
- Did the appropriate shift solenoids activate/deactivate?
Caution The vehicle speed must be below 56 km/h (35 mph) before shifting the select lever to "1" position, or the transaxle could overrun.
5. Reverse the order to downshift.
- Did the vehicle downshift from 4 to 3, 3 to 2, and 2 to 1?
- Did the appropriate shift solenoids activate/deactivate?
Note 4-3 downshift will be harsh when using the transaxle tester.
Torque converter clutch (TCC) engagement
Note This test should be performed on the road. If it is performed on a hoist, a technician may not feel the torque converter clutch engage.
Caution Do not depress the TCC switch with the transaxle in gear and the vehicle at a stop. Converter clutch may damage.
1. Accelerate and shift the vehicle up into third gear by using the tester. Hold the speed steady and depress the TCC switch.
- Did the torque converter engage?
- Did the engine speed drop?
- Did the TCC solenoid activate?
2. Release the TCC switch.
- Did the TCC solenoid deactivate?
- Did the TCC release?
- Did the engine speed increase?
3-2 timing/coasting clutch (3-2T/CCS) engagement
Note This test should be performed on the road. If it is performed on the hoist, a technician may not feel the 3-2 timing/coasting clutching disengage.
1. Accelerate and upshift the vehicle into third gear. Go to closed throttle. Depress the 3-2T/CCS switch.
- Did the 3-2 timing/coasting clutch disengage?
- Did the 3-2T/CCS solenoid deactivate (light on)?
2. Press lightly on the throttle, then release the 3-2T/CCS switch.
- Did the 3-2 timing/coasting clutch engage?
- Did engine braking occur?
- Did the 3-2 T/CCS solenoid activate (light of OFF)?
Note Coast clutch engagement at closed throttle will be harsh.
Turbine shaft speed (TSS) sensor inspection
Note This test may be performed on the hoist or on the road.
1. Set a voltmeter to 20 volt A.C.
1. Connect the positive lead to the (+) TSS jack.
2. Connect the negative lead to the (-) TSS jack.
2. Slowly accelerate the vehicle speed and monitor voltmeter.
- Did the voltage increase with an increase in vehicle speed?
Removing the transaxle tester and clearing diagnostic trouble code (DTC)
Caution Do not attempt to pry off connectors with a screwdriver. This will cause damage to connector and could result in a transaxle concern.
1. Disconnect the SSTs from the transaxle connector
2. Reinstall the emission harnesses. Verify the connections by pulling up on the harness.
3. Disconnect the transaxle tester power lead from the vehicle.
4. Erase all DTCs.
5. Rerun the On-Board Diagnostic Test.
6. Based on the transaxle tester results, proceed to the appropriate segment of this section for transaxle or electrical/wiring service.
7. Repeat the test with the transaxle tester to confirm repair.
Transaxle Range Switch Instruction
The transaxle tester allows the technician to operate the electrical portion of the Transaxle Range (TR) switch. The tester usage is divided into five steps.
1. Preliminary testing and diagnosis.
2. Installing the transaxle tester.
3. Testing the TR switch.
4. Testing the Park/Neutral and backup circuits.
5. Removing the transaxle tester and clearing DTCs.
Preliminary testing and diagnosis
Before any diagnostic testing is carried out on vehicle, some preliminary checks must be performed, as outlined below. Be sure to write down findings, especially any DTCs found, for future reference.
1. Verify that TR switch is properly adjusted in NEUTRAL.
2. Verify customer concern (e.g. when does concern occur?):
- upshift
- downshift
- coasting
- engagement
3. If concern involves noise or vibration, verify if it relates to any of the following:
- engine speed
- vehicle speed
- shift
- gear
- range
- temperature
4. Vehicle must be at normal operating temperature.
5. Inspect transaxle fluid level and condition.
6. Inspect for the following items:
- vehicle modifications
- electronic add-on items
- leaks
- proper linkage adjustments
- Perform vehicle On-Board Diagnosis Test.
Transaxle tester installation
Installing the transaxle tester at the TR switch connector results the separation of the TR switch from the vehicle electronics.
Note During tester usage, additional DTCs may be set. Therefore, it is important that all DTCs are erased after repairs have been made. To verify the elimination of all DTCs, rerun the On-Board Diagnosis Test.
Caution Do not attempt to pry off connectors with a screwdriver. This may damage the connector and could result in a transaxle concern.
1. Disconnect the emission harness at Transaxle Range (TR) switch connector.
Caution Route all cables away from heat sources.
2. Set the two-way switch in the down position. Install the SSTs (TR/MLP overlay, MLPS harness adapter) onto the tester. Connect the interface cable (cable I.D. "D") to the transaxle tester and then to the TR switch connector.
3. Turn the test select dial to the "TR/MLP SENSOR TEST" position.
4. Plug the transaxle tester power supply plug into the cigarette lighter socket. At this time, all LED's should illuminate for a short period and then turn off. This is the tester internal circuit inspection.
Testing the TR switch
Static testing procedures allow for shop testing of the TR switch on the vehicle or on the bench. Completion of these tests prove out the TR switch electronically.
Caution For resistance checks, be sure that the test select dial is set to the "TR/MLP SENSOR TEST" position or the ohmmeter may be damaged.
Note
- Using a digital volt-ohmmeter and the transaxle tester, perform the DTC troubleshooting as indicated on the DTCs which were displayed.
- Perform repairs as indicated by the pinpoint test. Always erase all DTCs, resistance test-TR switch retest and road test the vehicle after a repair.
Resistance test TR switch
1. Set the ohmmeter to the 5,000 ohm range.
2. Connect the positive lead of the ohmmeter to the TR/MLP jack.
3. Connect the negative lead of the ohmmeter to the SIGRTN jack.
4. Record the resistance at each position while moving the selector lever to each range position.
5. Refer to the chart for values.
- If out of specified range, perform the DTC troubleshooting.
Park/neutral, backup light and optional circuit voltage tests
Note LED will turn "RED" when the circuit is closed and turn "OFF" when the circuit is open.
1. Verify the test select dial is in "TR/MLP SENSOR TEST" position.
2. Press and hold each test button while moving the selector lever through each range position.
3. Monitor each "LED".
4. The status "LED" should indicate "RED" only in the indicated position. Refer to the overlay.
5. If the LED does not indicate "RED" in the desired position, or indicates "RED" in another position, first verify the TR switch alignment and then retest. If the switch fails, then replace.
Removing the transaxle tester and clearing diagnostic trouble code (DTC)
Caution Do not attempt to pry off connectors with a screwdriver. This will damage the connector and could result in a transaxle concern.
1. Disconnect the transaxle tester from the Transaxle Range (TR) switch connector.
2. Reinstall the emission harness. Verify the connection by pulling up on the harness.
3. Disconnect the transaxle tester power lead from vehicle
4. Erase all DTCs.
5. Rerun to the on-board diagnostic test.
6. Verify repair.