TOYOTA PREVIA 91-97 REPAIR MANUAL

4-22 DRIVEABILITY AND EMISSIONS CONTROLS

Fig. 62 Use an ohmmeter to measure the resistance betwei n

the terminals of the IAC valve—2TZ-FZE engine

7. After the engine rpm is kept at 1000-1200 for about 5 seconc
   check that the rpm drops about 200 rpm.


8. If the rpm operation is not as specified, check the IAC valve,
   and engine ECM.


9. Remove the jumper wire from the DLC1.

REMOVAL & INSTALLATION

inng

I See Figures 63 and 64

1. Remove the throttle body.


2. Remove the 4 screws to extract the IAC valve from the throttle body.
   Discard the gasket.
   To install:


3. Install a new gasket on the throttle body and place the IAC valie into
   position.


4. Secure the IAC valve on the throttle body.

Fig. 63 The IAC valve is attached to the throttle body

Fig. 64 Remove these four bolts to extract the IAC valve from

the throttle body

Coolant Temperature Sensor

OPERATION

A thermistor built into the engine coolant temperature sensor changes

the resistance value according to the engine coolant temperature.

The Engine Coolant Temperature (ETC) sensor's function is to advise the

ECM of changes in engine temperature by monitoring the changes in

coolant temperature. The sensor must be handled carefully during removal.

It can be damaged (thereby affecting engine performance) by impact.

TESTING

» See Figures 65 and 66

1. Disconnect the engine wiring harness from the ETC sensor.


2. Connect an ohmmeter between the ETC sensor terminals.

Acceptable

0.1 L

-20 0 20 40 60 80 100

(-4) (32) (68) (104) (140)(176)(212)

TEMPERATURE «C t°F)

Fig. 65 Engine Coolant Temperature (ETC) sensor values