Electric Control System
INSPECT TERMINAL ECT VOLTAGE1. INSPECT THROTTLE POSITION SENSOR SIGNAL
a. Turn the ignition switch to ON. Do not start the engine.
b. Connect a voltmeter between service connector and body ground.
c. While slowly depressing the accelerator pedal, check that terminal ECT voltage rises in sequentially.
If the voltage does not change in proportion to the throttle opening angle, there is a malfunction in the throttle position sensor or circuit.
2. INSPECT BRAKE SIGNAL
a. Depress the accelerator pedal until the terminal ECT indicates 8 V.
b. Depress the brake pedal and check the voltage reading from the terminal ECT.
Brake pedal depressed .... 0 V
Brake pedal released .... 8 V
If not as indicated, there is a malfunction in either the stop light switch or circuit.
3. INSPECT EACH UP SHIFT POSITION
a. Warm up the engine.
Coolant temperature: 80 °C (176 °F)
b. Turn the OD switch to "ON."
c. Place the pattern select switch in "Normal" and the shift selector into the D range.
d. During a road test (above 10 km/h or 6 mph) check that voltage at the terminal ECT is as indicated below for each up-shift position.
e. If the voltage rises from 0 V to 7 V in the sequence shown, the control system is okay.
f. The voltage could rise anywhere between O V to 8 V before the vehicle reaches 10 km/h (6 mph), the voltmeter indicates the current gear.
NOTE: Determine the gear position by a light shock or change in engine rpm when shifting.
INSPECTION OF ELECTRONIC CONTROL COMPONENTS
Terminal L(1)-GND - N-GND:
Terminal S(1)-GND - +B-GND:
1. INSPECT VOLTAGE OF ECT COMPUTER CONNECTOR
a. Remove the center cluster.
b. Turn on the ignition switch.
c. Measure the voltage at each terminal.
2. INSPECT SOLENOID
a. Disconnect the connector from the ECT computer.
b. Measure the resistance between S(1), S(2), S(3) and ground.
STD: 11 - 15 Ohms
c. Apply battery voltage to the solenoid.
Check that an operation noise can be heard from the solenoid.
NOTE: If there is foreign material in the solenoid valve, there will be no fluid control even with solenoid operation.
3. INSPECT NEUTRAL START SWITCH
Inspect that there is continuity between terminal L-C, 2-C and N-C.
4. INSPECT THROTTLE POSITION SENSOR
Using an ohmmeter, check the resistance between each terminal.
5. INSPECT NO.2 SPEED SENSOR
a. Jack up one front wheel.
b. Connect an ohmmeter to the speed sensor connector.
c. Spin the wheel and check that the meter needle deflects from 0 Ohm to infinity Ohms.
6. INSPECT NO.1 SPEED SENSOR IN COMBINATION METER
a. Remove the combination meter.
b. Connect an ohmmeter between terminals A and B.
c. Revolve the meter shaft and check that the meter needle repeatedly deflects from 0 Ohm to infinity Ohms.
7. INSPECT PATTERN SELECTION SWITCH
Inspect that there is continuity between terminal 5-4 and 5-3.
NOTE: As there are diodes inside, be careful of the tester probe polarity.
8. INSPECT BRAKE SIGNAL
Check that the brake light comes on when the brake pedal is depressed.
9. INSPECT OD SWITCH
Inspect that there is continuity between terminals 1 and 3.
10. INSPECT LOCK-UP MECHANISM
a. Warm up the coolant and ATF.
b. Connect a voltmeter between service connector and body ground.
c. Select the normal pattern.
d. Drive at around 70 km/h (43 mph) until 7, 5 or 3 V appears on the voltmeter (this is the lock-up range).
e. Depress the accelerator pedal and read the tachometer. If there is a big jump in engine rpm there is no lock-up.
NOTE: The lock-up clutch will turn ON only infrequently during normal 2nd and 3rd gear operation. To trigger this action, press the accelerator pedal to 50% or more of its stroke. At less than 50%, the voltage may change in the sequence 2 V - 4 V - 6 V - 7 V.