Oxygen Sensors - Toyota Land Cruiser 1988 Repair Manual

Fl-80 EFI SYSTEM - Electronic Control System
Oxygen Sensors
INSPECTION OF OXYGEN SENSOR
1. WARM UP ENGINE
Allow the engine to reach normal operating temperature.
2. INSPECT FEEDBACK VOLTAGE
Connect the positive ( +) probe of a voltmeter to terminal
VF1 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 rpm for approx. 1 20 seconds.
Short terminals TE1 and E1 of the check connector. ( Replace the ECU. )
And maintain engine speed at 2,500 rpm.
f
After replacing
Zero again
i
the oxygen
r
sensor
l
Check the number of times the voltmeter needle fluctuates in 10 seconds.
I
Less than 8 times 8 times
Zero
or more
Warm up the oxygen sensor with the engine at
(
Normal
2,500 rpm for approx. 120 seconds. And maintain
engine at 2,500 rpm.
8 times or more
Check the number of times the voltmeter needle
fluctuates in 10 seconds.
less than 8 times
Zero
Unshort terminals TE1 and E1 of the check con-
nector. And maintain engine speed at 2,500 rpm.
Measure voltage between termina_ls VF1 (VF2)
and E1.
!
0
v
More than 0 V
I
Read and record diagnostic codes. (See pages Fl-23, 24)
I
Normal code, code Nos.
Malfunction code(s)
21, 25, 26 and 28 (Ex. code Nos. 21, 25, 26 and 28)
(
Repair the relevant diagnostic code.
)
CD
1
2
®
4
CONTINUED ON PAGE Fl-81