Page 906 of 1865
7B TROUBLESHOOTING (G4A-EL)
Slippage Test
This step is performed to inspect slippage of the friction elements.
Preparation 1. Perform the preparation procedure shown in STEP 4 (STALL TEST). 2. Connect a tachometer to the engine and set it in the cabin.
3. Connect the EC-AT Tester and the adaptor harness between the EC-AT control unit and wiring
harness.
Procedure
Drive the vehicle in each of the gears indicated below and check whether the vehicle speed or engine
speed is above or below specification excessively as shown by the drum speed.
Driving condition
Speed
Drum speed (rpm)
No. Gears Other condition Speed
1,000 2,000 3,000 4,000
1 1st L range, Hold mode 11 (7) 22 (14) 33 (20) 44 (27)
2 1st D range, Economy mode 11 (7) 22 (14) 33 (20) 44 (27)
3 2nd S range, Hold mode Vehicle speed km/h (mph) 20 (12) 40 (25) 60 (37) 80 (50)
4 3rd D range, Hold mode 31 (19) 61 (38) 92 (57) 123 (76)
5 OD D range, Economy
mode 44 (27) 88 (55) 131 (81) 173 (107)
6 OD D range, Economy mode, Lock-up Engine speed (rpm) 1,000 2,000 3,000 4,000
76G07B-038
Evaluation
When there is no malfunction in the electrical system or hydraulic system, but vehicle speed or engine
speed is below specification, the problem can be attributed to slippage of the friction elements.
Driving conditions below specification Possible Cause
No.1 condition only Low and reverse brake
No.2 condition only One-way clutch
No.3 condition only 2-4 brake band
No.4 condition only Coasting clutch
No.5 condition only 3-4 clutch
No.1-No,5 conditions Forward clutch
No.6 condition only Lock-up piston (in torque converter)
76G07B-039
7B—40
Page 907 of 1865
TROUBLESHOOTING (G4A-HL) 7B
TROUBLESHOOTING (G4A-HL)
GENERAL NOTE
In the event of a problem with the automatic transaxle, the cause may be in the engine, power train,
hydraulic control system, or electrical control system.
When troubleshooting, therefore, it is recommended to begin from those points that can be judged
quickly and easily. The recommended troubleshooting sequence is described below.
STEP 4: TIME LAG TEST
Check time lag of oil pressure supply
STEP 6: OIL PRESSURE TEST Check line, throttle, and governor pressures
This step checks conditions surrounding the automatic
transaxle.
This step checks the electrical control system.
• Function of the electrical control system
• Components
This step checks the power train. • Friction element slipping • Torque converter capacity
This step checks operation of the hydraulic control system. • Accumulators • Friction elements slipping • Regulating valves
This step checks functions of the electric control system and
hydraulic control system.
This step checks major points of the hydraulic control system.
• Oil pump • Line pressure control • Throttle pressure control
• Governer pressure control
STEP 5: ROAD TEST Check items on road test
• Shift point • Shift schedule
• Kick-down • Shift shock • Lock-up and overdrive inhibition
By following the above 6 steps, the cause of the problem should be located.
As another guide to faster location of the causes of problems, the Quick Diagnosis Chart is included
at pages 7B—42, 43.
In this chart, a circle is used to indicate the components that might be the cause of trouble for 20
types of problems. It is only necessary to check those components indicated by circles, at each step
of the troubleshooting process, in order to quickly locate the cause of the problem.
76G07B-040
7B—41
Page 909 of 1865
TROUBLESHOOTING (G4A-HL) 7B
-ON VEHICLE-OFF VEHICLE-
Accele-rating
Shifting
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Excessive creep
No creep at all
No shift
Abnormal shift
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Frequent shifting
Excessive high or low shift point
No lock-up
No kick-down
Engine run away or slip when starting vehicle
Engine run away or slip when up- or down-shifting
Excessive N to D or N to R shift shock
Excessive shift shock when upshifting or downshifting
Excessive shift shock when changing range
Transaxle noisy in N or
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76G07B-042
7B—43
Page 913 of 1865
TROUBLESHOOTING (G4A-HL) 7B
STEP 2 (ELECTRICAL SYSTEM INSPECTION)
In this step, the function of the electrical control system (Inhibition of OD and lock-up) is checked. The
electrical control system components should be checked to determine if it functions correctly.
76G07B-048
O/D OFF Switch Inhibition Function
1. Warm up the engine and ATF.
2. Check that the D range, OD, and lock-up is
provided.
3. When driving the vehicle with D range, OD, and
lock-up selected, depress the O/D OFF switch and
check that OD and lock-up is cancelled.
4. If not cancelled, check the O/D OFF switch.
5. Release the O/D OFF switch after completion.
Cruise Control Switch Inhibition Function
1. Drive the vehicle in D range, OD, and lock-up
selected again.
2. Depress the Set switch of the cruise control and
check that OD and lock-up is cancelled.
3. If not cancelled, check the cruise control system.
4. Again drive the vehicle in D range, OD, and
lock-up.
5. Turn the Resume switch of the cruise control and
check that OD and lock-up is cancelled.
6. If not cancelled, check the cruise control system.
76G07B-051
7B—47
Page 915 of 1865
TROUBLESHOOTING (G4A-HL) 7B
STEP 3 (STALL TEST)
This step is performed to determine if there is slippage of the friction elements or malfunction of the
hydraulic components.
Preparation
Check the following items prior to testing:
1. Engine coolant, engine oil and ATF levels.
2. Warm the engine thoroughly to raise the ATF temperature to operating level (50—80°C, 122—176°F).
3. Engage the parking brake and use wheel chocks at the front and rear wheels.
Pull the parking brake Water temperature
ATF
83U07B-038
7B—49
Page 916 of 1865
7B TROUBLESHOOTING (G4A-HL)
Procedure
76G07B-054
1. Connect a tachometer to the engine.
2. Shift the selector lever to D range.
3. Depress the brake pedal firmly with the left foot and gradually depress the accelerator pedal with
the right foot.
4. Read and note the engine speed as soon as it becomes constant, then release the accelerator pedal.
Caution
Steps 3 to 4 must be performed within 5 seconds.
5. Shift the selector to N range and run the engine at idle speed for at least one minutes.
Note This one minute idle period is performed to cool the ATF and prevent oil degradation.
6. Perform stall tests for the following ranges in the same manner.
(1) 2 range
(2) 1 range
(3) R range
Standard stall speed:
FE engine F8 engine
D.S.L range 2430—2530 rpm D.S.L range 2180—2280 rpm
R range 2390—2490 rpm R range 2140—2240 rpm
Caution
Always provide adequate cooling time between individual range stall tests.
7B-50
Page 917 of 1865
TROUBLESHOOTING (G4A-HL) 7B
Evaluation
Condition Possible cause
Above specification
In all ranges Insufficient line pressure
Worn oil pump
Above specification
In all ranges Insufficient line pressure Oil leakage from oil pump, control valve, and/or transaxle case
Stuck pressure regulator valve
Above specification
In D 2, and 1 One-way clutch 1 slipping
Above specification
In D range only One-way clutch 2 slipping
Above specification In 2 range only 2-4 brake slipping Above specification
In R range only
Low and reverse brake slipping
Above specification
In R range only
Reverse clutch slipping
Above specification
In R range only Perform a road test, to determine if this is caused by the low and reverse brake or the reverse clutch, as follows:
a) Effective engine braking in 1 range Front clutch
b) No engine braking in 1 range Low and reverse brake
Within specification All shift control elements within transaxle are functioning
normally.
Below specification
Engine out of tune
Below specification One-way clutch slipping within torque converter
76G07B-055
7B—51
Page 918 of 1865
7B TROUBLESHOOTING (G4A-HL)
STEP 4 (TIME LAG TEST)
If the selector lever is shifted while the engine is idling, there will be a certain time lapse, or time lag,
before shock is felt. This step checks this time lag for checking the condition of the N-D and N-R ac-
cumulators, forward, reverse and one-way clutches, and low and reverse brake.
Preparation
Perform the preparation procedure shown in the STEP 3 (STALL TEST).
Procedure
1. Start the engine and check that the idle speed is 900 l5o rpm.
2. Shift from N range to D range
3. Measure the time it takes from shifting until shock is felt using a stop watch.
4. Shift the selector to N range and run the engine at idle speed for at least one minute.
5. Perform the test for the shift from N range to R range in the same manner.
Note
Make three measurements for each test and take the average value.
Specified time lag: N -> D range 0.4—1.2 second
N -> R range 0.4—1.5 second
Evaluation
Condition Possible Cause
N D shift
More than specification
Insufficient line pressure
N D shift
More than specification Forward clutch slipping
N D shift
More than specification One-way clutch 1 slipping N D shift
More than specification
One-way clutch 2 slipping N D shift
Less than specification N-D accumulator not operating properly
N D shift
Less than specification Excessive line pressure
N-R shift
More than specification
Insufficient line pressure
N-R shift
More than specification Low & reverse brake slipping
N-R shift
More than specification
Reverse clutch slipping N-R shift
Less than specification N-R accumulator not operating properly
N-R shift
Less than specification Excessive line pressure
76G07B-056
7B-52
