check engine MAZDA 626 1987 Workshop Manual

7B TROUBLESHOOTING (G4A-EL)
STEP 7 (ROAD TEST)
This step is performed to inspect for problems at the various ranges. If these tests show any problems,
adjust or replace by referring to the electronic system component or mechanical sections.
Caution
Perform the test at normal ATF operating temperature (50—80°C, 122—176°F).
D Range Test
Shift point, shift pattern, and shift shock
1. Shift the selector lever to D range and select the Power mode.
2. Accelerate the vehicle with half and full throttle valve opening.
Note
Throttle sensor voltage of the EC-AT Tester represents the throttle valve opening.
3. Check that 1-2, 2-3 and 3-OD up-shifts and downshifts and lock-up are obtained. The shift points
must be as shown in the D range (Power) shift diagram.
Note
a) Drum speed (rpm) of the EC-AT Tester represents the shift point.
b) Vehicle speed of the EC-AT Tester and speedometer and vehicle speed on a chassis
roller may not meet the specified shift pattern because of tire size. Therefore, check
the shift points with the Drum speed.
c) There is no lock-up when the coolant temperature is below 72°C (162°F).
d) There is no overdrive when the cruise control is operating and there is a 3 km/h (1.9
mph) difference between the pre-set cruise speed and vehicle speed, or set or resume
switch is ON.
e) There is no lock-up when the brake pedal is depressed.
4. Check the up-shifts for shift shock or slippage in the same manner.
5. While driving in OD, shift the selector lever to S range and check that 4-3 downshift immediately
occurs, then decelerate and check that engine braking effect is felt in only 3rd gear.
7B—34

7B TROUBLESHOOTING (G4A-EL)
Evaluation
Condition Possible Cause
No 1-2 up- or down-shift Stuck 1-2 shift solenoid valve
Stuck
1
-2 shift valve
No 2-3 up- or down-shift Stuck 2-3 shift solenoid valve Stuck 2-3 shift valve
No 3-OD up- or down-shift Stuck 3-4 shift solenoid valve Stuck 3-4 shift valve
No lock-up shift Stuck lock-up control solenoid valve Stuck lock-up control valve
Incorrect shift point Mis-adjusted throttle sensor Sticking shift valves
Excessive shift shock or slippage
Excessive shift shock Stuck accumulators Stuck or no one-way check orifice
Worn clutches, brakes, or one-way clutch
No engine braking effect Worn clutches or brakes
76G07B-035
Noise and vibration
Drive the vehicle in OD (lock-up), OD (no lock-up), 3rd (Hold) and check for abnormal noise or vibration.
Note
Abnormal noise and vibration can also be caused by the torque converter, drive shaft, or
differential. Therefore, checking of cause must be made with extreme care.
Kick-down
Drive the vehicle in OD, 3rd and 2nd gears and check that kick-down occurs for OD->3, OD->2, OD->1,
3->2, 3-+1, 2-> 1, and the shift points are as shown in the shift diagram.
S Range Test
Shift pattern
1. Shift the selector lever to S range and select the Economy mode.
2. Accelerate the vehicle and check that 1-2 and 2-3 up-shifts and down-shifts are obtained, and that
no overdrive and no lock-up are obtained.
Note
a) Inspections of shift shock and shift point are not necessary because these are the same
as those of the D Range Test.
b)ln S range, the shift patterns for Economy and Power modes are the same.
c) Shift points are the same as those of the D range (Power) shift diagram.
3. While driving in S range (Economy mode) and 3rd gear, select the Hold mode and check that 3rd
gear is held until the 3-2 down-shift point as shown in the S range (Hold) shift diagram is achieved.
4. Accelerate the vehicle with S range (Hold mode) and check that 2nd gear is held.
7B i—36

TROUBLESHOOTING (G4A-EL) 7B
76G07B-036
Noise and vibration
Drive the vehicle in 2nd gear (Hold mode) and check for abnormal noise or vibration.
Note
Abnormal noise and vibration can also be caused by the torque converter, drive shaft or
differential. Therefore, checking of cause must be made with extreme care.
L Range Test
Shift pattern
1. Shift the selector lever to L range and select the mode.
2. Accelerate the vehicle and check that the 1-2 up- and down-shiftings are obtained and that no 3rd
gear, no OD, and no lock-up are obtained.
Note
Inspection of shift shock and shift point are not necessary because these are the same
as those of the D Range Test.
3. Drive in 1st gear then decelerate and check that engine braking effect is felt.
Note
a) In L range, the shift patterns for Economy and Power modes are the same.
b) Shift points are the same as those of the D range (Power) shift diagram.
4. While driving in S range (Hold mode) and 2nd gear, shift the selector lever to L range and check
that 2nd gear is held until the 2-1 down-shift point as shown in the L range (Hold) shift diagram
is achieved.
5. Accelerate the vehicle in L range (Hold mode) and check that 1st gear is held.
7B—37

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

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

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

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

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

TROUBLESHOOTING (G4A-HL) 7B
STEP 5 (ROAD TEST)
This step is performed to inspect for problems at the various ranges.
If
these tests show any problems,
adjust or replace by referring to the mechanical sections.
Perform the test at normal ATF operating temperature (50—80°C, 122—176°F).
D Range Test
Shift point, shift pattern, and shift shock
1. Shift the selector lever to D range and depress the OD OFF switch.
2. Accelerate the vehicle with half (4/8) and full (8/8) throttle valve opening.
3. Check that 1-2, 2-3 and 3-OD up-shifts and downshifts and lock-up are obtained. The shift points
must be as shown in the D range shift diagram.
Note
a) Vehicle speed on a chassis roller may not meet the specified shift diagram because of
tire size.
b) There is no lock-up or OD when the coolant temperature is below 72°C (162°F), and when
the OD OFF switch is depressed.
4. Check the up and down shifts for shift shock or slippage.
5. While driving in 3rd (50—60 km/h, 31—37 mph) shift the selector lever to 2 range and check that
3-2 downshift immediately occurs, then decelerate and check that engine braking effect is felt in
2nd gear.
D range shift diagram
FE engine
Caution
8/8 n
-OD
0 20(12) 40(25) 60(37) 80(50) 100(63) 120(74) 140(87)
Vehicle speed km/h (mph)
76GC7B-057
7B—53

TROUBLESHOOTING (G4A-HL) 7B
1 Range Test
Shift pattern
1. Shift the selector lever to 1 range.
2. Accelerate the vehicle with half (4/8) and full (8/8) throttle valve opening.
3. Check that the 1-2 up- and down-shifts are obtained and that no 3rd gear, no OD, and no lock-up
are obtained. The shift points must be as shown in the 1 range shift diagram.
Note
Vehicle speed on a chassis roller may not meet the specified shift diagram because of tire
size.
4. Check the up and down-shifts for shift shock or slippage.
5. Drive in 1st gear then decelerate and check that engine braking effect is felt.
1 range shift diagram
FE engine
8/8-1 i
7/8-
6/8-2
2 CT>
I 4/8-a> a. o a> 3/8-
o
2/8-
1/8-
20 40 60 80 (25) (37) (50)
Vehicle speed km/h (mph)
80 100 120 140 (63) (74) (87) (12)
76G07B-059
7B—55