![](../../../img/13/AK305781AB00ENG.png)
![](../../../img/13/AK305782AB00ENG.png)
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1.Disconnect the oxygen
sensor connector and connect the special tool Test harness
(MB991316) to the connector on the oxygen sensor
side.
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![](../../../img/13/AKX01624AR00ENG.png)
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2.Make sure that there is
continuity (11 - 18 Ω at 20°C) between
terminal No. 1 (red clip of special tool) and No. 3 (blue
clip of special tool) on the oxygen sensor
connector. 3.If there is no continuity, replace
the oxygen sensor. 4.Warm up the engine until
engine coolant is 80°C or higher. 5.Perform
a tracing for 5 minutes or more with the engine speed of
4,500 r/min.
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![](../../../img/13/AKX01624AP00ENG.png)
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6.Connect a digital voltage
meter between terminal No. 2 (black clip of special tool)
and No. 4 (white clip of special tool). 7.While
repeatedly racing the engine, measure the oxygen sensor
output voltage.
Standard
value:
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; incorrect connection can
damage the oxygen sensor.
- Be careful the heater is broken when
voltage of beyond 12 V is applied to the
oxygen sensor heater.
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note |
If the sufficiently high
temperature (of approximate 400°C or more)
is not reached although the oxygen sensor is
normal, the output voltage would be possibly low
although the rich air-fuel ratio. Therefore, if
the output voltage is low, use a jumper wire to
connect the terminal No. 1 (red clip of special
tool) and the terminal No. 3 (blue clip of
special tool) of the oxygen sensor with a
(+) terminal and (-) terminal of 12 V
power supply respectively, then check
again.
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8.If the sensor is defective, replace the
oxygen sensor.
note |
For removal and installation
of the oxygen sensor, refer to GROUP 15 -
Exhaust Manifold. .
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