Transaxle Tester Testing Procedures
ELECTRICAL SYSTEM COMPONENTS [LA4A-EL]Transaxle Tester Instruction
The transaxle tester allows a technician to operate the electrical portion of the transaxle independent of the vehicle electronics. The transaxle tester usage is divided into five steps.
1.Preliminary testing and diagnosis.
2. Installing the transaxle tester.
3. Static testing-vehicle OFF.
4. Dynamic testing-vehicle 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. It 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. Check fluid level and condition.
4. Visually inspect the vehicle for the following items:
- vehicle modifications
- electronic add-on items
- leaks
- proper linkage adjustments
- Perform vehicle on-board diagnosis test.
Installing The Transaxle Tester (Set Up Procedures)
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 Turbine Shaft Speed (TSS) connector on the oil pump body in the LH wheel arch.
2. Turn the tester solenoid select switch 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 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, allow the ATF to cool.
4. Remove the square head plug shown in the figure.
5. Connect the SSTs to the line pressure inspection port.
6. Plug the transaxle tester power supply plug into the cigarette lighter receptacle. At this time, all LED's should illuminate for a short period and then turn off. This is the tester internal circuit check.
7. 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 prove out the transaxle electronically.
CAUTION: For resistance checks, be sure that the tester solenoid select switch is set to the "OHMS CHECK" position or damage to the ohmmeter may result.
Resistance/Continuity Tests
- Refer to Pinpoint Test to be performed "On Board Diagnostics" based on the DTC displayed.
- Using a volt-ohmmeter and the transaxle tester, perform the Pinpoint Tests as indicated in "On Board Diagnostics" 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.
Transaxle Solenoid And Sensors Resistance Tests
Solenoids Electronic Pressure Control (EPC), Shift Solenoid No.1 (SS1), Shift Solenoid No.2 (SS2), Torque Converter Clutch (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, SS1, SS2, TCC, 3-2T/CCS) jack.
4. Record the resistance.
5. Refer to the chart for the values.
6. If out of range, refer to the following pinpoint tests.
- Pinpoint test E (EPC)
- Pinpoint test A (SS1, SS2)
- Pinpoint test C (TCC)
- Pinpoint test G (3-2T/CCS)
Transaxle Fluid Temperature (TFT)
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.
6. It out of range, refer to the Pinpoint test BA, BB, BC, BD, BE, BF.
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.
6. If out of range, refer to the Pinpoint test F.
Solenoid Voltage Tests
NOTE: LED will turn "GREEN" when solenoid activates and turn "OFF" when deactivated. LED will turn "RED" it 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 power circuit.
4. Connect voltmeter negative lead to the appropriate solenoid.
5. Using the voltmeter, check 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 "ON"
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 switch on tester to the GEAR SELECT "1" position.
3. Set the vehicle in PART.
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 damage will result.
1. Observe the line pressure. Record the value. Line pressure should go to maximum. If not, refer to A Automatic Transaxle Symptom Troubleshooting [LA4A-EL] or Pinpoint test "E" concerning the EPC solenoid.
2. Depress the EPC switch. Line pressure should drop to a minimum value. Record the value. If not, refer to A Automatic Transaxle Symptom Troubleshooting [LA4A-EL) or Pinpoint Test "E".
Transaxle Engagement
NOTE: Engagement will be harsh and line pressure will be at maximum regardless of the EPC switch during reverse check.
1. Set the Bench/Drive switch to the "DRIVE" mode.
2. Rotate the gear select switch to GEAR SELECT "1".
3. Turn GEAR SELECT switch to 3/R.
(1) Shift vehicle from PARK to REVERSE.
- Did vehicle shift into REVERSE?
- Was engagement harsh?
(2) Shift vehicle from REVERSE to PARK.
4. Turn GEAR SELECT switch to 1.
(1) Depress EPC switch. Line pressure should drop to idle pressure.
(2) While holding the EPC switch down, shift vehicle from PARK to DRIVE.
- Did the vehicle shift into DRIVE?
- Was engagement smooth?
(3) Shift the vehicle from DRIVE to PARK.
(4) Release EPC switch. Pressure should return to maximum.
(5) With the EPC switch released, repeat step 5.
Engagement should be firm.
Upshift Downshift
NOTE:
- GEAR SELECT SWITCH must be in GEAR SELECT "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, a mechanic 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 switch is in first gear 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. Verify that the gear select switch is in "1" position. Move the selector shift lever into D range and accelerate to 24 km/h (15 mph). Select second gear by rotating the gear selector switch 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 "Y 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 must be below 56 km/h (35 mph) before selecting gear select "1" position, or the transaxle could overrun.
5. Reverse the order to downshift.
NOTE:
- 4-3 downshift will be harsh when using the transaxle tester.
- Does the vehicle down shift from forth gear to third gear, third gear to second gear, and second gear to first gear?
- Did the appropriate shift solenoids activate/deactivate?
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. Damage to converter clutch may result.
1. Accelerate and shift the vehicle up into third gear by using the tester (Refer to drive test). Hold the speed steady and depress the TCC switch.
- Does the torque converter engage?
- Does 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 mechanic may not feel the 3-2 timing/coasting clutching disengage.
1. Accelerate and upshift the vehicle into second gear. Go to closed throttle. Depress the 3-2T/CCS switch.
- Does 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.
NOTE:
- Coast clutch engagement at closed throttle will be harsh.
- Does the 3-2 timing/coasting clutch engage?
- Did engine braking occur?
- Did the 3-2 T/CCS solenoid activate (light off)?
Turbine shaft speed (TSS) sensor function check.
NOTE: This test may be performed on the hoist or on the road.
3. Set a voltmeter to 20 volt A.C.
Connect the positive lead to the (+) TSS jack. Connect the negative lead to the (-) TSS jack.
Slowly accelerate the vehicle and monitor voltmeter.
- Does the voltage increase with 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 and TSS 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 from the continuous test.
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. Confirm the servicing by repeating the test with the transaxle tester.
TR/MLP Tester Instruction
The transaxle tester allows the mechanic to operate the electrical portion of the transaxle range (TR) switch. The MLP 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 a 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, does it relate to any of the following:
- engine speed
- vehicle speed
- shift
- gear
- range
- temperature
4. Vehicle must be at normal operating temperature.
5. Check transaxle fluid level and condition.
6. Check for the following items:
- vehicle modifications
- electronic add-on items
- leaks
- proper linkage adjustments
- Perform vehicle On-Board Diagnosis Test.
Installing The Transaxle Tester (Set Up Procedures)
Installing the transaxle tester at the TR switch connector results the separation of the vehicle electronics from the TR switch 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 will damage the connector and could result in a transaxle concern.
1. Disconnect the emission harness at Transaxle Range (TR) switch connector.
NOTE: For in vehicle testing, use the SST
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 switch to the "TR/MLP SENSOR TEST" position.
4. Plug the transaxle tester power supply plug into the cigarette lighter receptacle.
At this time, all LED's should illuminate for a short period and then turn off. This is the tester internal circuit check.
Testing The TR Switch
Static testing procedures allow for shop testing of the transaxle in the vehicle or on the bench. Completion of these tests prove out the TR switch electronically.
CAUTION: For resistance checks, be sure that the tester select switch is set to the "MLP SENSOR TEST" position or damage to the ohmmeter may result.
NOTE:
- Using a digital volt-ohmmeter and the transaxle tester, perform the pinpoint test "D" as indicated on the DTCs which were displayed.
- Perform repairs as indicated by the pinpoint test. Always retest and road test the vehicle after a repair.
TR Switch Resistance Tests
1. Set the ohmmeter to the 1,000 ohm range.
2. Connect the positive lead of the ohmmeter to the MLP jack.
3. Connect the negative lead of the ohmmeter to the SIGRTN jack.
4. Move the selector lever into each range position.
5. Record the resistance at each position.
6. Refer to the chart for values.
7. If out of range, perform the pinpoint test "D".
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. Set the tester select switch to the "TR/MLP SENSOR TEST" position.
2. Press and hold each 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 Diagnostic Trouble Codes (DTCs). (Unlatch the center button of the star tester while the codes are being displayed on a key on engine off (KOEO) on-board diagnosis test)
5. Return to the on-board diagnostic test.
6. Verify that the customer concern has been eliminated.