![](../../../img/13/AK603902AB00ENG.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. 2.Measure resistance between terminal No. 1
and No. 3 on the oxygen sensor connector.
Standard value: 11 - 18 Ω (at
20°C) 3.If there is no continuity,
replace the oxygen sensor. 4.Warm up the engine
until engine coolant is 80°C or higher.
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![](../../../img/13/AKX01624AP00ENG.png)
![](../../../img/13/AKX01624AR00ENG.png)
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5.Perform a tracing for 5
minutes or more with the engine speed of 2,500
r/min. 6.Connect a digital voltage meter between
terminal No. 2 and No. 4. 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 (to be the red clip of special
tool) and the terminal No. 3 (to be the 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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