Oxygen Sensor (W/ Twc - Toyota 4A-FE Repair Manual

EFI SYSTEM - Electronic Control System
Fl-145
f
-
L .;
Voltmeter
v _ ---~
EM7603
Oxygen Sensor (w/ TWC)
INSPECTION OF OXYGEN SENSOR
1. WARM UP ENGINE
2.
Allow the engine to reach normal operating temperature.
INSPECT FEEDBACK VOLTAGE (VF)
Connect the positive
(+)
probe of a voltmeter to terminal
Vf 1 of the check connector, and negative (-) probe to
terminal E1. Perform the test as follows:
Warm up the oxygen sensor with the engine at 2,500
r--~~~~~~~~~~~~~~~~~~~~~~
rpm for approx. 90 seconds.
Using SST, connect terminals TE1 and E1 of the ( Replace the ECU.
)
check connector.
4
SST 09843-1 8020 I
And maintain engi-ne speed at 2.500 rpm
---
Zero again
I
After replacing
I the oxygen sen sor
I
I
,
I
Check the number of times the voltmeter needle fluctuates in
1 0
seconds.
I
4A-FE
Less than 8 times
4A-FE
I ze
8
times
or
more ·
ro
- -
•
Warm
up
the oxygen sensor with the engine
at
2,500
I
rpm for approx. 90 seconds. And maintain engine at
Normal
2,500 rpm.
'
I
Check the number of times the voltmeter needle
6 times or more
fluctuates in 1 0 seeonds.
Zero
4A-FE Less than 8 times
I
4A-GE Less than 6 times
-
Disconnect terminals TE1 and E1 of the check
connector. And maintain engine speed at 2,500 rpm.
Measure voltage between terminals VF 1 and E1.
OV
'
More than 0 V
I
Read and record diagnostic codes. (See pages Fl-28 to 31)
I
Normal code Malfunction code(s}
and code
21
(Ex.
code 21)
I
,
Repair the relevant diagnostic code.
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CONTINUED ON PAGE Fl-146