![](../../../img/13/ACF02774AB00ENG.png)
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1.Disconnect the oxygen
sensor connector and connect the special tool test harness
(MB991658) to the connector on the oxygen sensor
side. 2.Measure the resistance between terminal
No. 1 and No. 2 of the oxygen sensor
connector. Standard value: 4.5 - 8.0
Ω (at 20°C) 3.If the
resistance deviates from the standard value, replace the
oxygen sensor. 4.Warm up the engine until the
engine coolant temperature is 80°C or
higher. 5.Perform a racing for 5 minutes or more
with the engine speed of 2,000 r/min. 6.Connect
the digital voltmeter between terminal No. 3 and No.
4. 7.While repeatedly racing the engine, measure
the oxygen sensor output voltage. Standard
value:
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Engine
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Oxygen sensor
output voltage
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Remarks
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When racing the
engine
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0.6 - 1.0
V
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If you make the
air-fuel ratio rich by racing
the engine repeatedly, a normal
oxygen sensor will output a
voltage of 0.6 - 1.0
V.
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caution |
- Be very careful when connecting the
jumper wire, or incorrect connection can
damage the oxygen sensor.
- Exercise sufficient care so as not to
apply voltage exceeding 8 V onto the
oxygen sensor heater; otherwise the
heater may be damaged.
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note |
If the temperature of sensing
area does not reach the high temperature (of
approximately 400°C or more) even though
the oxygen sensor is normal, the output voltage
would be possibly low in spite of the rich
air-fuel ratio. Therefore, if the output
voltage is low, use a jumper wire to connect the
terminal No. 1 and No. 2 of the oxygen sensor
with the (+) and (-) terminals of 8
V power supply respectively, then check the
voltage again.
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8.If the voltage deviates from the standard
value, replace the oxygen sensor.
note |
For removal and installation
of the oxygen sensor, refer to GROUP 15 -
Exhaust Pipe and Main Muffler .
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