Inspection of Electronic Control Components

INSPECTION OF ELECTRONIC CONTROL COMPONENTS





1. INSPECT VOLTAGE OF ECT ECU CONNECTOR
(a) Remove the center console box.
(b) Turn on the ignition switch.
(c) Measure the voltage at each terminal.

NOTE: Component tests for malfunctions found in Step 1 begin at Step 4.











2. INSPECT SOLENOID
(a) Disconnect the connector from the ECT ECU.





(b) Measure the resistance between S1, S2, SL, S4 and ground.

STD: 11 - 15 ohms

(c) Apply battery voltage to the solenoid. Check that an operation noise can be heard from the solenoid.





3. CHECK SOLENOID SEALS
If there is foreign material in the solenoid valve, there will be no fluid control even with solenoid operation.
(a) Check No. 1, No. 2 and No. 4 solenoid valves.
^ Check that the solenoid valve does not leak when low-pressure compressed air is applied.
^ When supply battery voltage to the solenoid, check that the solenoid valve opens.





(b) Check the lock-up solenoid valve.
^ Applying 5 kg/cm2 (71 psi, 490 kPa) of compressed air, check that the solenoid valves open.
^ When supply battery voltage to the solenoids, check that the solenoid valves do not leak the air.

If a malfunction is found during voltage inspection (step 1.), inspect the following components.





4. INSPECT NEUTRAL START SWITCH
Inspect that there is continuity between terminals L-C, 2-C and N-C.









5. INSPECT THROTTLE POSITION SENSOR
Using an ohmmeter, check the resistance between each terminal.









6. INSPECT NO.2 SPEED SENSOR
(a) Remove No. 2 speed sensor.
(b) Connect an ohmmeter between the terminals.
(c) Bring a magnet close to then away from the sensor tip and check that the meter needle deflects from 0 ohms to infinity ohms.





7. INSPECT NO. 1 SPEED SENSOR IN COMBINATION METER
(Analog Meter)
(a) Remove the combination meter.
(b) Connect an ohmmeter between terminals SPD and GND.
(c) Revolve the meter shaft and check that the meter needle repeatedly deflects from 0 ohms to infinity ohms.





8. INSPECT PATTERN SELECT SWITCH
Inspect that there is continuity between 5 and each terminal.





NOTE: As there are diodes inside, be careful of the tester probe polarity.





9. INSPECT O/D SWITCH





Inspect that there is continuity between terminals 1 and 3.





10. INSPECT TRANSFER POSITION SWITCH





Check that there is continuity between each terminal.





11. INSPECT TRANSMISSION AND TRANSFER FLUID TEMPERATURE SENSOR





Measure the resistance between terminals.





11. INSPECT TRANSFER FLUID TEMPERATURE WARNING COMPUTER
(a) Connect the battery positive (+) lead to terminal 1.
(b) Connect the negative (-) lead to terminal 3.
(c) Connect a 3.4 W test bulb between battery positive (+) lead and terminal 2.
(d) Short the terminals 4 and 5. Check that the bulb lights.

If operation is not as specified, replace the computer.