1987 MAZDA 626 check engine

TROUBLESHOOTING (G4A-EL) 7B
STEP 4 (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
79G07C-084
7B-27

7B TROUBLESHOOTING (G4A-EL)
STEP 5 (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 condition of the 1-2, N-R, and N-D
accumulators, forward, and one-way clutches, 2-4 brake band, and low and reverse brake.
Preparation
76G07B-030
Procedure
1. Start the engine and check the idle speed in P range.
Idle speed: 900 ±58 rpm
2. Shift from N range to D range
3. Measure the time it takes from shifting until shock is felt, with 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 following shifts in the same manner.
(1) N D range (Hold mode)
(2) N -» R range
Note
Make three measurements for each test and take the average value.
Specified time lag: N -> D range
N -»• R range
Evaluation
Condition Possible Cause
N D (Economy) shifting
More than specification
Insufficient line pressure Forward clutch slipping One-way clutch 1 slipping One-way clutch 2 slipping N D (Economy) shifting
Less than specification N-D accumulator not operating properly
Excessive line pressure
N-D (Hold) shifting
More than specification
Insufficient line pressure Forward clutch slipping 2-4 brake band slipping One-way clutch 1 slipping N-D (Hold) shifting
Less than specification 1-2 accumulator not operating properly
Excessive line pressure
N R shifting
More than specification
Insufficient line pressure Low and reverse brake slipping Revese clutch slipping N R shifting
Less than specification N-R accumulator not operating properly
Excessive line pressure
86U07B-038
0.5—1.0 second
0.5—1.0 second
7B-30

TROUBLESHOOTING (G4A-EL) 7B
STEP 6 (OIL PRESSURE TEST)
This step checks line pressures for checking the hydraulic components and for oil leakage.
Line Pressure Test
Preparation
1. Perform the preparation procedure shown in STEP 4 (STALL TEST).
2. Connect a tachometer to the engine.
3. Connect the SST to the line pressure inspection hole (square head plug L)
Procedure
76G07B-031
1. Start the engine and check the idle speed in P range
Idle speed: 900 -so rpm
2. Shift the selector lever to D range and read the line pressure at idle.
3. Depress the brake pedal firmly with the left foot and gradually depress the accelerator pedal with
the right foot.
4. Read the line pressure as soon as the engine speed becomes constant, then release the accelera-
tor pedal.
Caution
Steps 3 to 4 must be performed within 5 seconds.
5. Shift the selector lever to N range and run the engine at idle for at least one minute.
6. Read the line pressure at idle and engine stall speeds for each range in the same manner.
7B—31

TROUBLESHOOTING (G4A-EL) 7B
Throttle Pressure Test
This step checks line pressure for checking the hydraulic components and for improper adjustment
of throttle cable.
Preparation
1. Perform the preparation procedure shown in STEP 4 (STALL TEST).
2. Connect a tachometer to the engine.
3. Connect the SST to the throttle pressure inspection hole (square head plug T).
Procedure
76G07B-034
1. Start the engine and check the idle speed in P range.
Idle speed: 900 _5o rpm
2. Shift the selector lever to D range and read the throttle pressure at idle.
3. Depress the brake pedal firmly with the left foot and gradually depress the accelerator pedal with
the right foot.
4. Read the throttle pressure as soon as the engine speed becomes constant, then release the ac-
celerator pedal.
Caution
Steps 3 to 4 must be performed within 5 seconds.
Specified throttle pressure:
Throttle pressure kPa (kg/cm2, psi)
When idling 39-88 (0.4—0.9, 6—13)
At stall speed 471—589 (4.8—6.0, 68—85)
Evaluation
Throttle pressure Possible location of problem
Not within specification
Throttle valve sticking Pressure regulator valve sticking Improper adjustment of throttle cable
7B—33

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